Their pilots each saw 'two flat, silver discs', with some flying within 100ft.
Air traffic control then spotted six UFOs on their radars before they suddenly disappeared.
The encounter, which was probed by the UK Airprox Board, happened on December 30 just before 9am.
A Boeing 777 was flying over the Scientology headquarters in East Grinstead minutes from touchdown when all three pilots on the flightdeck spotted the objects about 100ft below them moving slowly or stationary, according to the report.
A following Boeing 767 also spotted the two white or silver discs, which were at approximately 1,000ft above ground. An Airbus A319 then landed before the objects disappeared from ATC screens.