31 July 1927 (Germany) — H. Steindorff flying a Rohrbach-Roland, powered by three BMW engines, sets a new speed record with a useful load of 500-kg, and a distance record with a pay load of 1000-kg , covering 1,438.680-miles at 127.632-mph ; also a speed record for 2,000-km with a 1,000-kg useful load , and a distance record with 2000-kg, flying 1,087.60 miles .

31 July 1948 (USA) — The New York International Airport begins operations and becomes the largest airport in the United States.

31 July 1952 (USA) — The First transatlantic helicopter flight when Capt. Vincent H. McGovern and 1st Lt. Harold W. Moore piloted two Sikorsky H-19’s from Westover, Mass., to Prestwick, Scotland (3,410 mi). Trip was made in five stops, with a flying time of 42 hr., 25 min. (15-31 July 1952).

31 July 1957 (USA/Canada/Faroe Islands/Greenland/Iceland) — “DEW” Line reported to be fully operational. The Distant Early Warning Line, also known as the DEW Line or Early Warning Line, was a system of radar stations in the far northern Arctic region of Canada, with additional stations along the North Coast and Aleutian Islands of Alaska, in addition to the Faroe Islands, Greenland, and Iceland. It was set up to detect incoming Soviet bombers during the Cold War, and provide early warning of a land based invasion.