21 January 1973 : Death of Francois Portron, French WWI flying ace.
21 January 1972 : First flight of the Lockheed S-3 B Viking
21 January 1970 : The Boeing 747 makes its first commercial flight from New York to London for Pan American.
21 January 1968 : 1968 Thule Air Base B-52 crash: A Boeing B-52G-100-BW Stratofortress, 58-0188, c.n. 4642256, of the 528th Bomb Squadron, 380th Bomb Wing, from Plattsburgh AFB, New York, carrying four hydrogen bombs crashes on the ice seven miles from Thule Air Base, Greenland at 1639 hrs. AST, 1 crew member killed; all four B-28 weapons are consumed in post-crash fire, however one bomb unaccounted for after debris is audited; extensive contamination of site and several relief workers exposed to radiation.] This accident caused the Department of Defense to suspend Operation Chrome Dome, the nuclear airborne alert program of SAC.
21 January 1963 : First flight of the Fairchild Hiller FH-1100, an American single-engine, single two-bladed rotor, light helicopter
21 January 1960 : Avianca Flight 671, a Lockheed Constellation, crashes on landing at Sangster International Airport, killing 2 of 7 crew and 35 of 39 passengers on board in Jamaica's worst aviation accident.
21 January 1960 : Little Joe 1 B, Launch Escape System test of the Mercury spacecraft, lifts off from Wallops Island, Virginia with Miss Sam, a female rhesus monkey on board.
21 January 1960 : Death of John Stanley Chick, British WWI fighter ace, and RAF officer until the end of WWII.
21 January 1958 : The last Fokker C. X in military service, the Finnish Air Force FK-111 target tower, crashed, killing the pilot and winch-operator.
21 January 1952 : Second prototype of Arsenal VG 90 turbojet strike fighter design for the Aeronavale, VG-90.02, first flown June 1951, crashes this date killing pilot Claude Dellys.
21 January 1952 : The Saab 210 experimental delta-winged research aircraft makes its first flight in Sweden.
21 January 1951 : Lockheed P2V-4 Neptune, of VP-22, deployed to WestPac during the Korean War on 1 November 1950 and based at Naha Air Base, Okinawa, is lost this date due to starboard engine failure during takeoff. The P2V crashed and sank in 20 fathoms of water one mile off the end of the runway. There were 11 survivors and two crewmen were listed as missing (their bodies were later recovered).
21 January 1951 : The U. S. Air Force F-84 Thunderjet makes its first kill, when F-84 pilot Lieutenant Colonel William E. Bertram shoots down a MiG-15 during the Korean War.
21 January 1951 : First non-stop unrefuelled transatlantic crossing by a jet is made by an English Electric Canberra.
21 January 1950 : First flight of the Tupolev Tu-75, a Soviet 4 engine military transport prototype variant of the Tu-4 bomber.