UNCLASSIFIED // PUBLIC RELEASERELEASE 07 · OCTOBER 23, 2026
PENTAGON UFO FILE · DOCUMENT · DOW-UAP-D163Air Intelligence Information Report, Sweden, 1953
This three-page Air Intelligence Information Report (IR-12-54) from the U.S. air attaché’s office in Stockholm is dated 13 January 1954 and rated B-2. It was prepared by Maj. Burt Rowen, assistant air attaché, and approved by Lt. Col. Herbert J. Rogers, acting air attaché. Its sources are listed as the press and a personal contact, and it went to USAFE intelligence and the U.S. Army attaché in Stockholm.
The press account
The core is a translated newspaper interview with Capt. Ulf Christiernsson, chief pilot of the airline Transair. At 1437 on 17 December 1953, flying a DC-3 from Bulltofta to Bromma on autopilot at about 2,150 meters, he and his crew chief say a shining, metallic object came toward them about 600 meters below, just above the cloud tops, heading southwest at what he guessed was the speed of sound. Seen first diagonally from the right as a narrow shape and then from above as nearly round, it was in view six or seven seconds and left no exhaust or contrail. He called it possibly “an unmanned robot,” not a meteor. The article also quotes a Defense Staff communiqué that no Swedish aircraft was in the area and that an investigation was under way, and the air force chief saying radar records would be checked.
The attaché’s caveat
The report adds a character sketch from a source in the Royal Swedish Air Board who had known the pilot all his life. That source called him charming and well-liked but also “most untrustworthy,” though the report adds that the Swedish Air Force generally rated him one of the country’s best pilots; and personally doubted the story. The office said it was seeking more information; no result appears in this file, and nothing in it confirms the object on radar or from other witnesses.
The official description
From war.gov/UFO, released October 23, 2026, quoted in full
This document is an Air Intelligence Information Report (AIIR), a standardized U.S. Air Force reporting form used to record raw information of potential intelligence value for later analysis. The form served as a primary vehicle for U.S. Air Force field intelligence collection throughout the early Cold War, until defense-wide reporting standards were established in the early 1960s.
This AIIR records a December 17, 1953, incident near Hässleholm, Sweden, translated from a local media report. At 1437 hours, Transair chief pilot Captain Ulf Christiernsson and crew chief Olle Johansson reported observing an object approaching their DC-3 from the opposite direction, approximately 600 meters (1,969 feet) below their aircraft, which was flying at about 2,150 meters (7,054 feet). The aircrew described a “shining metal spherical elliptical object” and estimated its speed as approximately the speed of sound. Christiernsson described the object as strongly metallic, nearly round, and slightly elliptical. He reported that it remained visible for six to seven seconds, produced no visible exhaust or condensation trail, and initially appeared to him to be a jet or possibly an unmanned “robot.” The Swedish Defense Staff reportedly identified no Swedish aircraft in the area at that time and stated that it would examine possible radar observations. The report also includes a brief character sketch of Christiernsson based on the account of a personal contact, who characterized him as “most untrustworthy,” and notes that Swedish authorities had begun an investigation into the incident.
All descriptive and estimative language contained in this report reflects the reporter’s subjective interpretation at the time of the event. Such characterizations should not be interpreted as a conclusive indication of the presence or absence of any intrinsic object features or performance characteristics.
AARO Comment: Based on the reported aircraft altitude and relative separation, the object’s reported altitude was approximately 1,550 meters (5,085 feet). Under standard atmospheric conditions, the speed of sound at that altitude is approximately 748 mph.