1901 – Wilbur and Orville Wright make the first of a series of test glides at Kill Devil Hills near Kitty Hawk, North Carolina. Their redesigned biplane glider No. 2 has a larger wing area and wing control worked by a pilot’s hip-cradle device.

1908 – Orville Wright warns Glenn Curtiss that the wing flaps used in the AEA’s June Bug are an infringement of the Wrights’ patent.

1911 – First ever commercial cargo to be carried by an aircraft. The General Electric company paid £100 to have a case of electric lamps flown from Shoreham to Hove in England.

1912 – Harriet Quimby, the first licensed female pilot in the United States, as part of an Air Show spectacular flew around the Boston Light. During the flight, her Berliot plane was caught in turbulent air and nose-dived, plummeting both Quimby and a meet organizer passenger to their deaths in Dorchester Bay.

1913 – First example of skywriting by Milton J Bryant over Seattle WA, in forming a business of aerial advertising.

1914 – Britain’s first airplane passenger service is launched. The short-lived service flies from Leeds to Bradford and back, on half-hour intervals.

1916 – The United States Navy armored cruiser North Carolina becomes the first ship to launch an aircraft by catapult while underway, launching a Curtiss flying boat piloted by Lieutenant Godfrey Chevalier.

1928 – Amelia Earhart becomes the first woman to fly across the Atlantic Ocean

1929 – Curtiss-Wright Corporation is formed, result of a merger of 12 companies associated with Curtiss Aeroplane and Motor Company of Buffalo, New York, and Wright Aeronautical of Dayton, Ohio. The new corporation constructs light aircraft at the Curtiss plant in Buffalo, New York; heavy aircraft and flying boats at its Keystone Aircraft Corporation subsidiary in Bristol, Pennsylvania; civil aircraft at its Curtiss-Robertson subsidiary in St. Louis, Missouri; and Curtiss and Wright aircraft engines at the Wright factory in Paterson, New Jersey.

1933 – First flight of the Douglas DC-1, an American prototype and first model of the famous United States DC (Douglas Commercial) commercial transport aircraft series

1933 – Wiley Post began First solo flight around world in a Lockheed Vega, Winnie Mae

1937 – Amelia Earhart and navigator Fred Noonan disappeared over the central Pacific Ocean en route in their Lockheed Electra 10E to Howland Island during an attempt to circumnavigate the world.

1938 – “Yankee Clipper” completes First passenger flight over Atlantic.

1938 – Howard Hughes, with crew members Harry Connor, Tom Thurlow, Richard Stoddart and Ed Lund, begin a record-breaking round-the-world flight in a specially modified Lockheed Super Electra. They cut in half the time set by Wiley Post 1933; their flying time is 71 hours, 11 min, 10 seconds

1942 – US air offensive against nazi-Germany begins.

1948 – First flight of the Vickers Viscount

1950 – The first scheduled passenger service flown by a gas-turbine powered airliner (turboprop) is British European Airway’s (British European Airways) Vickers V. 630 Viscount

1959 – QANTAS introduces the Boeing 707 on its Sydney-San Francisco route, the first transpacific service flown by jet.

1965 – The Mariner 4 flyby of Mars takes the First close-up photos of another planet.

1967 – A deckfire on the USS Forrestal caused by an unintentional firing of a Zuni rocket by an electrical short-circuit from the underwing rack of an McDonnell Douglas F-4 Phantom II at 1051 hrs. holes the fuel tank of an McDonnell Douglas A-4 Skyhawk. Spilled fuel ignites and ordnance on the ready jets is set off by the blaze. Twenty-six aircraft are destroyed or jettisoned, 31 others are damaged, 132 crewmen die, 62 are injured and two are missing. The last major fire is extinguished at 4 a.m. on 30 July. See: 1967 USS Forrestal fire. Among lost airframes are Douglas A-4E Skyhawk, BuNos 149996, 150064, 150068, 150084, 150115, 150118, 150129, 152018, 152024, 152036, 152040; McDonnell Douglas F-4B Phantom II, 153046, 153054, 153060, 153061, 153066, 150069, 150912; and North American RA-5C Vigilantes of RVAH-11, 148932, 149284, and 149305.

1976 – The National Air and Space Museum (NASM) of the Smithsonian Institution opens in Washington, D. C., United States, it is a center for research into the history and science of aviation and spaceflight, as well as planetary science and terrestrial geology and geophysics.

1988 – Iran Air Flight 655, an Airbus A300, is shot down over Iranian waters by the missile cruiser USS Vincennes; all 290 people on board are killed.

1996 – TWA Flight 800, a Boeing 747, explodes in mid-air above the ocean off East Moriches, New York, killing all 230 people on board

2011 – The Space Shuttle Atlantis returns to Earth at the end of STS-135, the final mission of the Space Shuttle Program.

Above is an abbreviated list of a few of the aviation events and milestones that occurred in July.  For a more complete list see this Wikipedia page.