Carlos Antonio de los Santos Montiel radar-visual encounter

Saturday, 3 May 1975. Carlos Antonio de los Santos Montiel, a 23-year-old Mexican pilot, was flying a Piper PA-24 Comanche, registration XB-XAU, from Zihuatanejo to Mexico City International Airport. He was alone on board. He had climbed to 14,500 feet. Below him ran the airway past Lake Tequesquitengo, in Morelos.

He felt it before he saw it. "I felt the sensation, turned, and saw an object coming over the upper surface of the wing," he later said, "and said my God, what is this." A domed disc, about 3 metres across, was flying alongside him. Another quickly appeared at the left wingtip.

He described two plates joined together at the rim, with a cupola on top. Opaque grey. A sort of windshield. No rivets, completely smooth. Each hung over a wing, by one account just 20 centimetres above it.

Then a third object came straight at him. "I was petrified," he recalled. It seemed about to collide head-on with the windshield. Instead it passed beneath the fuselage. His airspeed dropped from 140 to 120 knots. The controls froze. The landing gear lever locked. The plane seemed to float, and was lifted to 15,800 feet.

He radioed Mexico City. "I have three unidentified visual objects flying around me." Then: "I'm not controlling the plane. Apparently someone is controlling it." After 18 minutes the objects left, one by one, toward the volcanoes Popocatépetl and Iztaccíhuatl. The controls returned to normal.

In Mexico City, controllers Julio César Interián Díaz and Emilio Estañol López were watching. Interián saw a blip separate and execute "a 270-degree turn in a radius of 3 or 4 miles at a speed of 450-500 nautical miles per hour." One account says the three echoes merged into one and sped toward Popocatépetl. On 9 May the Syracuse Herald-Journal quoted both men. Separate radar screens, they said, had shown an unidentified object moving alongside a small plane.

APRO field investigator Fernando J. Téllez Pareja took the case. In August 1975 the APRO Bulletin ran it on the front page as "UFOs 'Escort' Mexican Aircraft." MUFON's Skylook covered it that month too. In mid-June, J. Allen Hynek met the pilot privately at his hotel. Hynek came as a private researcher. Project Blue Book had closed in December 1969.

Then came the Men in Black, in the pilot's own telling. About two weeks after the flight, before a planned television interview with Pedro Ferriz, two black Ford Galaxie limousines boxed him in. Four tall men with very pale skin warned him in Spanish, in a mechanical tone. In mid-June, on the steps of Hynek's hotel, one of the same men spoke to him. "You were already warned once. You are not to talk about your experience."

On 7 May 1975, Dr. Luis Amezcua, head of aviation medicine at the airport, reportedly concluded the pilot had low blood sugar. He had not eaten since 8 p.m. the night before, and Amezcua inferred a hallucination. Other accounts say he was cleared to fly, and Mexicana later hired him. On Metabunk, commenters raised hypoxia in an unpressurised cabin and flagged discrepancies in dates and aircraft type. In 2010 he told Ana Luisa Cid that hypoxia makes you sick and dizzy, "but you don't hallucinate."

In July 2023, Milenio obtained the original tower recordings from SENEAM through a transparency request. The case has since appeared on The Unexplained Files and Discovery Latinoamérica. It is often paired with the 1976 case of student pilot Rafael Pacheco Pérez. No source has ever alleged a hoax.