Within Lleida UFOs
Was Lleida's Strongest UFO Case a Balloon?
The 1968 Lleida case stands out because pilots, radar and a failed photo mission all pointed to a serious but plausibly conventional event.
On this page
- What the pilots and radar reportedly saw
- Why the photo mission did not settle it
- How the stratospheric balloon explanation fits
Page outline Jump by section
Introduction
Lleida’s 17 May 1968 pilot-and-radar case is probably the province’s strongest official UFO file, but not because it proves anything exotic. It matters because the report combined trained military witnesses, radar tracking, an attempted photographic mission and a later, cautious official conclusion that the object was almost certainly real but still not firmly identified. The most plausible ordinary explanation is a high-altitude stratospheric balloon, and the details of the case fit that idea better than the headline version often suggests: a metallic-looking object apparently above Lleida, very high, slow or static from the pilots’ viewpoint, rising over several hours, and beyond the practical reach of the aircraft sent to inspect it. The weakness is that the photo attempt failed, the file does not appear to pin down a launch source, and later retellings often lean harder into mystery than the surviving evidence can bear.[Scribd+2files.bluebookfiles.org]es.scribd.comAvistamiento de OVNI en LleidaAvistamiento de OVNI en Lleida
Why this case stands above Lleida’s other files
The 1968 incident stands out in Lleida’s UFO history because it was not just a casual sighting from the ground. Spain’s declassified UFO collection includes reports in which personnel or equipment of the Air Force were involved, and the Ministry of Defence describes the archive as 80 files and about 1,900 pages covering strange aerial phenomena in Spanish airspace between 1962 and 1995.[Biblioteca Virtual de Defensa]bibliotecavirtual.defensa.gob.esBiblioteca Virtual de Defensa Expedientes OVNIBiblioteca Virtual de Defensa Expedientes OVNI Lleida appears in that national record only a few times, which makes the 1968 file unusually important for the province: it is the one where aircraft, radar and an attempted photographic check all converge.[Biblioteca Virtual de Defensa]bibliotecavirtual.defensa.gob.esBiblioteca Virtual de Defensa Listado de títulosBiblioteca Virtual de Defensa Listado de títulos
That does not make it a confirmed extraordinary craft. It makes it a good case for asking how an unidentified aerial report should be weighed. The file’s value lies in the chain of observations: pilots reported a strange object; a radar station reportedly detected something at very high altitude; faster aircraft were sent with cameras; the object remained difficult to reach; and the eventual photographic opportunity produced no usable image. Those are exactly the details that make a UFO case sound strong, but they also create a practical path towards a conventional explanation.[Scribd]es.scribd.comAvistamiento de OVNI en LleidaAvistamiento de OVNI en Lleida
What the pilots and radar reportedly saw
The core report places the event on the morning of 17 May 1968. According to the file summary reproduced in the declassified Spanish UFO archive, two C-5 aircraft, identified as F-86 Sabres, told the EVA-1 radar station that they had a strange object in sight, roughly over Lleida. It was described as static, metallic in colour and apparently made up of two superimposed bodies, with the lower one elongated or fuselage-like. EVA-1 then detected the object in the same position at about 76,000 feet, with an upward movement.[Scribd]es.scribd.comAvistamiento de OVNI en LleidaAvistamiento de OVNI en Lleida
The altitude is one of the most important details. A reported 76,000 feet is far above normal commercial-aviation levels and well above the practical ceiling of the F-86. The National Museum of the United States Air Force gives the F-86A Sabre a ceiling of 49,000 feet; other museum and aircraft references for F-86 variants cluster around roughly 48,000 to 50,000 feet.[Air Force Museum+2Aerospace Museum]nationalmuseum.af.milAir Force Museum North American F-86A SabreAir Force Museum North American F-86A Sabre In plain terms, the first pilots could see the object but were never likely to fly up alongside it for a close inspection.
The file then says two C-8 aircraft, identified in summaries as F-104 Starfighters, took off later with cameras. They reportedly made visual contact from about 15 nautical miles away while at 45,000 feet. The object’s appearance changed in the pilots’ descriptions: it was compared to an inverted spear-point, then to the body of a squid, and later to something like an aircraft with tip tanks hanging from its tail. This variation is not unusual in distant aerial observations, especially when an object is bright, high, poorly resolved and seen from a moving aircraft. It does, however, weaken any attempt to treat the shape description as a precise engineering observation.[Scribd]ro.scribd.comAvistamiento de OVNI en LleidaAvistamiento de OVNI en Lleida
The radar story continued into the afternoon. Summaries of the file state that the height-finding radar at EVA-1 detected two very close echoes with slight upward movement, and that contact was lost at around 18:00 local time, with the object reported at about 83,000 feet over position BM-33.[Scribd]es.scribd.comAvistamiento de OVNI en LleidaAvistamiento de OVNI en Lleida The long duration and gradual rise matter because they are more balloon-like than aircraft-like. A powered aircraft may loiter, climb or depart, but a high-altitude object apparently drifting or rising slowly for hours is exactly the sort of behaviour investigators would compare with a stratospheric balloon.
Why the photo mission did not settle it
The attempted photography is one of the case’s most intriguing details, but also one of its most frustrating. The second pair of aircraft were reportedly sent with cameras, and they climbed to about 59,000 feet. The object was then said to be around 81,000 feet, leaving a vertical gap of roughly 7 kilometres. The pilots could not align the cameras properly under those conditions, and the eventual camera firing produced no useful result because the film was reportedly spoiled.[Scribd]ro.scribd.comAvistamiento de OVNI en LleidaAvistamiento de OVNI en Lleida
This is where the case often becomes misunderstood. A failed photo mission is not the same as photographic evidence. It shows that the military took the report seriously enough to try to document it, but it does not add an image that later readers can inspect. The strongest surviving evidence remains testimonial and instrumental: pilot reports, radar detection and the internal military handling of the incident.[Segre.com]segre.comdefensa saca la luz dos informes sobre ovnis vistos lleida hace casi anos 5017defensa saca la luz dos informes sobre ovnis vistos lleida hace casi anos 5017
The failed photo mission also explains why the case did not close cleanly at the time. Had the cameras captured a clear image, the file might have supported a more confident identification. Instead, investigators were left with a high object, seen and tracked at distance, described in shifting visual terms and detected by radar without a recovered payload or confirmed launch origin. That is enough to make the case serious in an archival sense, but not enough to make it extraordinary.
How the stratospheric balloon explanation fits
The balloon explanation fits because the reported behaviour lines up with known high-altitude balloon characteristics: great altitude, slow apparent motion, a climb over time, a reflective or metallic appearance in sunlight, and difficulty for intercepting aircraft to approach closely. Modern weather and research balloons routinely operate in the stratosphere; weather balloons carry radiosondes and are tracked by ground equipment, while high-altitude balloon platforms commonly reach tens of thousands of feet. The US National Weather Service describes weather balloons as a key platform for upper-air observations, carrying radiosondes tracked by specialised ground equipment.[National Weather Service]weather.govOpen source on weather.gov.
The reported heights in the Lleida file are also plausible for balloon-like objects. High-altitude ballooning sources commonly describe flights reaching around 80,000 to 100,000 feet, while historical stratospheric balloon programmes have operated at comparable or greater altitudes.[Instructables]instructables.comThe Ultimate High Altitude Weather Balloon Data LoggerThe Ultimate High Altitude Weather Balloon Data Logger NASA’s own high-altitude balloon work describes balloon systems operating in the 60,000 to 80,000-foot range for controlled-altitude flight demonstrations, showing that the altitude band in the Lleida file is not inherently exotic.[NASA TechPort]techport.nasa.govOpen source on nasa.gov.
The shape descriptions are also compatible with a balloon-plus-payload interpretation, even though they do not prove it. A distant balloon can look like a bright metallic body, while its suspended instrument package, parachute, rigging or radar reflector can create the impression of a second body, an elongated lower section or a strange attached form. That is a better match for the “two superimposed bodies” description than a conventional aircraft at 76,000 to 83,000 feet hovering over the area for hours.[Scribd]es.scribd.comAvistamiento de OVNI en LleidaAvistamiento de OVNI en Lleida
The strongest reason not to call the case solved without qualification is the missing source. The file summary and later public retellings point towards a stratospheric balloon, and one search snippet from the Defence-file copy says the assessment was that it was “with almost complete certainty” a stratospheric balloon, but the publicly accessible summaries do not, on their own, identify a specific balloon launch, operator, trajectory record or recovered payload.[files.bluebookfiles.org]files.bluebookfiles.orgAVISTAMIENT O DE FENOMENOS EXTRANOSAVISTAMIENT O DE FENOMENOS EXTRANOS That distinction matters. “Plausibly a balloon” is well supported; “identified as this exact balloon” is not established by the commonly available evidence.
What radar adds, and what it does not
Radar involvement makes the case stronger than a simple visual sighting, but radar does not automatically make a UFO report extraordinary. In this case, the radar reportedly supported the pilots’ claim that there was a real object at a high altitude. That matters because it reduces the likelihood that the whole episode was only a visual illusion, a reflection in a canopy or a mistaken view of a small nearby object.[Scribd]es.scribd.comAvistamiento de OVNI en LleidaAvistamiento de OVNI en Lleida
At the same time, radar is not a full identification tool by itself. A radar echo can confirm that something reflective or trackable is present, but the file details do not show that radar revealed what it was. The report’s two close echoes could even sit comfortably with a balloon system made of more than one radar-reflective part, such as a balloon and suspended equipment. That reading is consistent with the file’s own visual description of a compound object, but it remains an inference rather than a recovered fact.[Scribd]es.scribd.comAvistamiento de OVNI en LleidaAvistamiento de OVNI en Lleida
The time span also cuts both ways. Radar contact lasting until around 18:00 makes the object harder to dismiss as a momentary mistake, but it also makes a fast, manoeuvring craft less necessary as an explanation. A slow high-altitude balloon can remain visible or trackable for long periods, especially if winds carry it gently and observers below perceive it as nearly stationary.
The aircraft limit is central to the case
The aircraft detail is not just colourful background; it is central to understanding why the pilots could not identify the object. The first aircraft, F-86 Sabres, were not capable of reaching the reported altitude band. The second aircraft, F-104 Starfighters, were far better high-performance interceptors, but even they reportedly reached 59,000 feet while the object was above 80,000 feet.[Scribd]ro.scribd.comAvistamiento de OVNI en LleidaAvistamiento de OVNI en Lleida
This gap helps explain the apparent drama without requiring exotic behaviour. The pilots were not chasing something that constantly evaded them by impossible manoeuvres in the surviving summary. They were trying to inspect something already far above their operating position. Specialist sources on the F-104 note that although the Starfighter could reach dramatic altitudes in record-setting zoom climbs, sustained operating altitude was much lower; one technical discussion of the F-104 flight envelope places maximum altitude with afterburner around 50,000 to 55,000 feet, with higher altitudes possible by trading speed for height in a zoom climb.[starfighter.no]starfighter.noOpen source on starfighter.no.
That makes the reported failure to close in less mysterious. The aircraft-versus-object mismatch is what one would expect if the target was a balloon or balloon train in the stratosphere. It also explains why the case could be both “strong” and “probably conventional”: strong because trained crews and radar were involved, conventional because the object’s altitude and behaviour fit known balloon operations better than a powered aircraft.
What later reporting strengthened or weakened
Later reporting has mostly strengthened the case as an important local archive item, not as an unexplained marvel. When Spanish media covered the release of the Defence UFO files in 2016, Lleida’s 1968 incident was listed among the Catalan cases, and local reporting emphasised that the Defence documents included summaries, witness interviews, military analysis and meteorological information.[Verne]verne.elpais.comOpen source on elpais.com. That helps readers understand why the case matters: it was not merely a rumour retold decades later, but part of the official declassified record.
What later reporting has weakened is the more sensational version. Public summaries often repeat the elements that sound most dramatic — pilots, radar, high altitude, cameras — but the same details also point towards a balloon. The longer the object remained high and slowly ascending, the less necessary it becomes to imagine a structured craft under intelligent control. The failed film removes the most valuable possible evidence, and the absence of a specific balloon launch record prevents a neat closed-case ending.[Scribd]es.scribd.comAvistamiento de OVNI en LleidaAvistamiento de OVNI en Lleida
For Lleida’s province-level UFO history, the fair reading is therefore balanced. The 1968 case is the strongest official Lleida file because it had multiple military-observation layers. It is also the case where a conventional explanation is most technically persuasive. The balloon question is not a sceptical afterthought bolted onto the story; it sits at the heart of the evidence.
Best assessment
The best assessment is that the 17 May 1968 Lleida object was probably a high-altitude stratospheric balloon or balloon system, but the public record does not allow a fully specific identification. The reasons for the balloon interpretation are concrete: the object was very high, apparently slow or static, metallic-looking, possibly compound in shape, rising from about 76,000 to 83,000 feet, difficult for aircraft to approach and present for hours. Those details fit balloon behaviour better than they fit a conventional aircraft, and they do not require extraordinary technology.[Scribd+2Scribd]es.scribd.comAvistamiento de OVNI en LleidaAvistamiento de OVNI en Lleida
The reasons for caution are equally clear. The photographs failed, no recovered object is cited in the accessible summaries, and no exact balloon launch has been tied publicly and conclusively to the file. That leaves the case in a useful middle category: not weak enough to dismiss as a simple story, not strong enough to support an extraordinary claim, and best understood as a serious military UFO report whose own details point towards a plausible conventional cause.
Amazon book picks
Further Reading
Books and field guides related to Was Lleida's Strongest UFO Case a Balloon?. Use these as the next step if you want deeper reading beyond the article.
The UFO Experience
Explores how serious UFO cases should be evaluated rather than sensationalized.
The Demon-Haunted World
Provides critical thinking tools for assessing extraordinary claims.
eBay marketplace picks
Marketplace Samples
Live-tested eBay searches with available results related to this page.
Endnotes
1.
Source: es.scribd.com
Title: Avistamiento de OVNI en Lleida 17 5 1968
Link:https://es.scribd.com/document/328831642/Avistamiento-de-OVNI-en-Lleida
2.
Source: files.bluebookfiles.org
Title: AVISTAMIENT O DE FENOMENOS EXTRANOS
Link:https://files.bluebookfiles.org/pdfs/1968.00%20-%20NARA%20-%20SpanishUFOFiles%20-%201968-05-17_avistamiento_en_lerida.pdf
3.
Source: segre.com
Title: defensa saca la luz dos informes sobre ovnis vistos lleida hace casi anos 5017
Link:https://www.segre.com/es/sociedad/161025/defensa-saca-la-luz-dos-informes-sobre-ovnis-vistos-lleida-hace-casi-anos_5017.html
4.
Source: ro.scribd.com
Title: Avistamiento de OVNI en Lleida 17 5 1968
Link:https://ro.scribd.com/document/328831642/Avistamiento-de-OVNI-en-Lleida
5.
Source: weather.gov
Link:https://www.weather.gov/gjt/education_corner_balloon
6.
Source: instructables.com
Title: The Ultimate High Altitude Weather Balloon Data Logger
Link:https://www.instructables.com/The-Ultimate-High-Altitude-Weather-Balloon-Data-Lo/
7.
Source: techport.nasa.gov
Link:https://techport.nasa.gov/projects/89368
8.
Source: starfighter.no
Link:https://starfighter.no/envel-e.html
9.
Source: archive.org
Title: Spanish UFOFiles
Link:https://archive.org/details/SpanishUFOFiles
10.
Source: archive.org
Link:https://archive.org/stream/OnomasticaMaremmana/Onomastica%20Maremmana_djvu.txt
11.
Source: archive.org
Link:https://archive.org/download/jufoh/jufoh.pdf
12.
Source: lleida.com
Title: 1971 02 23 avistamiento en barcelona huesca lerida mar cantabrico compressed
Link:https://www.lleida.com/sites/default/files/u4626/1971-02-23_avistamiento_en_barcelona-huesca-lerida-mar_cantabrico_compressed.pdf
13.
Source: scribd.com
Link:https://www.scribd.com/document/704360145/FAA-Order-JO-7340-2K-dtd-9-10-20-post
14.
Source: scribd.com
Title: Nous Paper d Ovnis num 3 4
Link:https://www.scribd.com/document/636261768/Nous-Paper-d-Ovnis-num
15.
Source: es.scribd.com
Title: 17121 Mis Ovnis Favoritos 2001
Link:https://es.scribd.com/document/726638903/17121-Mis-Ovnis-Favoritos-2001
16.
Source: scribd.com
Link:https://www.scribd.com/document/636261544/Nous-Papers-d-Ovnis-num-2
17.
Source: bibliotecavirtual.defensa.gob.es
Title: Biblioteca Virtual de Defensa Expedientes OVNI
Link:https://bibliotecavirtual.defensa.gob.es/BVMDefensa/exp_ovni/es/micrositios/inicio.do
18.
Source: bibliotecavirtual.defensa.gob.es
Title: Biblioteca Virtual de Defensa Listado de títulos
Link:https://bibliotecavirtual.defensa.gob.es/BVMDefensa/exp_ovni/es/consulta/indice_campo.do?campo=idtitulo
19.
Source: verne.elpais.com
Link:https://verne.elpais.com/verne/2016/10/25/articulo/1477394008_803441.html
20.
Source: nationalmuseum.af.mil
Title: Air Force Museum North American F-86A Sabre
Link:https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/196118/north-american-f-86a-sabre/
21.
Source: aerospaceca.org
Title: north american f 86f sabre
Link:https://www.aerospaceca.org/aircraft-collection/north-american-f-86f-sabre
22.
Source: bibliotecavirtual.defensa.gob.es
Title: defensa.gob.es Títulos
Link:https://bibliotecavirtual.defensa.gob.es/BVMDefensa/exp_ovni/es/consulta/indice_campo.do?campo=idtitulo&posicion=1
23.
Source: bibliotecavirtual.defensa.gob.es
Link:https://bibliotecavirtual.defensa.gob.es/BVMDefensa/es/publicaciones/listar_numeros.do?busq_anyo=1968&busq_dia=29&busq_infoArticulos=true&busq_mes=5&campoOrden=fechaPublicacion&descendente=true&forma=
24.
Source: bibliotecavirtual.defensa.gob.es
Link:https://bibliotecavirtual.defensa.gob.es/BVMDefensa/es/publicaciones/listar_numeros.do?1D66C31B=5C2E47C1074EA1AA748C96959323F84D&busq_anyo=1968&busq_dia=21&busq_idPublicacion=&busq_infoArticulos=true&busq_mes=5&campoOrden=nombreordenar&descendente=false
25.
Source: mapa.gob.es
Title: 2845 all
Link:https://www.mapa.gob.es/ministerio/pags/biblioteca/fondo/pdf/2845_all.pdf
Additional References
26.
Source: youtube.com
Title: What If a Fighter Jet Fired Missiles at a UFO? | WION Podcast
Link:https://www.youtube.com/watch?v=9PO944Vw3dw
Source snippet
Pilot Spots UFO Zoom Past Mid-Flight | The Proof Is Out There...
27.
Source: youtube.com
Title: Navy Pilot Reveals the UFO Encounter That Changed His Life
Link:https://www.youtube.com/watch?v=nn1EdNXgBxM
Source snippet
What If a Fighter Jet Fired Missiles at a UFO? | WION Podcast...
28.
Source: youtube.com
Title: Javier Sierra: The secret report on UFOs in Franco’s Spain
Link:https://www.youtube.com/watch?v=_lSEWzNb2rc
Source snippet
UFO: TRUMP OPENS the PENTAGON FILES | RTVE News...
29.
Source: youtube.com
Title: UFO: TRUMP OPENS the PENTAGON FILES | RTVE News
Link:https://www.youtube.com/watch?v=FpwGbhB0f_M
Source snippet
Navy Pilot Reveals the UFO Encounter That Changed His Life...
30.
Source: cufos.org
Link:https://cufos.org/PDFs/books/Catalogue_of_200_Type_I_UFO_Events_in_Spain_and_Portugal.pdf
31.
Source: aerospaceutah.org
Link:https://www.aerospaceutah.org/museum/our-collections/aircraft-collection/f-86f-sabre/
32.
Source: facebook.com
Link:https://www.facebook.com/CharlieTop10s/posts/at-first-glance-it-looks-unreal-almost-like-something-generated-but-it-is-actual/1431349069037106/
33.
Source: theworld.com
Link:https://theworld.com/~reinhold/DW-Espanol-1P.pdf
34.
Source: digitalcombatsimulator.com
Link:https://www.digitalcombatsimulator.com/en/products/sabre/?PAGEN_1=2
35.
Source: openheritage3d.org
Link:https://openheritage3d.org/data
Topic Tree