February 18 – The 1956 Scottish Airlines Malta air disaster: a Scottish Airlines Avro York crashes near Żurrieq, Malta due to pilot error, killing all 50 on board.
April 1 – TWA Flight 400, a Martin 4-0-4, crashes on takeoff at Greater Pittsburgh International Airport, killing 22 of the 36 on board; 14 survive.
April 2 – Northwest Orient Airlines Flight 2, a Boeing 377 Stratocruiser, ditches into Puget Sound after takeoff from Seattle–Tacoma International Airport after the cowl flaps are incorrectly set for takeoff; four passengers and a flight attendant die.
June 20 – Linea Aeropostal Flight 253, a Lockheed L-1049 Constellation, crashes into the Atlantic Ocean off Asbury Park, New Jersey. All 74 passengers and crew on board are killed.
June 24 – In the 1956 BOAC Argonaut accident, a Canadair C-4 Argonaut, crashes shortly after taking off from Kano Airport, Nigeria, into a thunderstorm, killing 32 of the 38 passengers and 3 of the seven crew.
June 30 – The 1956 Grand Canyon mid-air collision between United Airlines Flight 718, a DC-7 and TWA Flight 2, a Lockheed Constellation, over the Grand Canyon, kills all 128 aboard both aircraft; operating under Visual Flight Rules, the planes fail to see each other and collide; the Federal Aviation Administration is created in the aftermath