List of accidents and incidents involving commercial aircraft 1919 – 1959
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.