Sourcing status: Sourced and not flagged as disputed (see Sources section below for the 2 citations this entry is based on).
Brazilian integrated air defense networks simultaneously tracked 21 distinct unidentified objects moving across national airspace over Sao Paulo and Rio de Janeiro. The Brazilian Air Force scrambled multiple Mirage III and F-5E Tiger fighters; pilots achieved visual contact but the objects outmaneuvered every intercept attempt. The Air Force Minister of Aeronautics publicly acknowledged the event the following day. The incident directly influenced Brazil's subsequent legislation mandating routine transfer of all UAP investigation files to the National Archives.
Documents
Brazilian Air Force intercept logs - 1986-05-19
Government of Brazil official press release
Sources
primary_doc: Brazilian Air Force official press release, 1986-05-20