On the night of May 19, 1986, between roughly 8:00 PM and midnight, the airspace over São Paulo, Rio de Janeiro, and the southern Brazilian states was penetrated by up to 21 unidentified aerial objects, producing what the Brazilian Air Force (FAB) officially designated 'A Noite Oficial dos OVNIs' — the Official UFO Night — the only formal acknowledgement of mass UFO activity by a national military in the twentieth century. The incident began at 8:00 PM when traffic controllers at São José dos Campos airport tracked multiple high-speed radar contacts over the Paraíba Valley. Within ninety minutes, contacts had spread across Minas Gerais, São Paulo, and Rio de Janeiro airspaces, appearing simultaneously on civilian ATC and FAB radar at CINDACTA I.
FAB commanders scrambled five interceptors: three Mirage IIIEs from Anápolis and two F-5Es from Santa Cruz. The fighters engaged at high altitude. Squadron Leader Márcio Jordão in his Mirage reported visual contact with an object 'with a lighted perimeter' at 18,000 metres that departed vertically at speeds he estimated at Mach 10. Captain Kléber Marinho in an F-5E achieved radar lock on an object over Baía da Ilha Grande; the object reversed direction instantly and accelerated to Mach 15, breaking lock. Multiple commercial airline crews on Varig and VASP routes reported visual encounters, including a Varig 727 captain who radioed 'we are surrounded' before the objects departed. FAB total radar contact time was more than four hours.
At 6:00 AM on May 20, Minister of Aeronautics Brigadier Octávio Moreira Lima held an unprecedented press conference confirming the entire engagement as 'physical and real' and acknowledging the objects' performance capabilities were 'superior to any known aircraft.' The FAB released portions of the radar tapes and pilot testimony in 2009 under Brazil's public-disclosure laws. The Official UFO Night remains the single most significant declassified air-force-UFO engagement in world history and the only case in which a national defense minister explicitly confirmed interception of craft whose performance exceeded all terrestrial aerospace capability.