June 4

• 2013 – Braving unsettled weather in the Midwestern United States, Solar Impulse aircraft HB-SIA completes the third leg of its trip across the contiguous United States, arriving at Lambert–St. Louis International Airport outside St. Louis, Missouri, where it is housed in an inflatable temporary hangar – the conventional hangar originally earmarked for it had been destroyed by a powerful storm on 31 May – in the first real-world test of an inflatable hangar. During the flight, the aircraft flies under cirrus clouds for the first time, and, to the surprise of its designers, its batteries continue to charge at 30 to 50 percent despite the diminished sunlight. The 1,040-km (646-mile) flight from Dallas-Fort Worth International Airport in Texas, which takes 21 hours 22 minutes at an average speed of 49 km/h (30.4 mph) and reaches a maximum altitude of 24,000 feet (7,315 meters), is the second-longest in terms of duration ever made in a solar-powered aircraft, exceeded only a flight of over 26 hours HB-SIA itself made in July 2010.^[1][2]

• 2012 – After a Libyan militia force takes control of part of Tripoli International Airport in Tripoli, and demands the release of a kidnapped militia leader, a gun battle breaks out between the militiamen and Libyan government forces. Government authorities arrest 30 militiamen.^[3]

• 2012 – An American unmanned aerial vehicle strike in Pakistan kills Abu Yahya al-Libi, a leading al-Qaeda official.^[4]

• 2012 – A student at the Brazilian Air Force Academy was killed when he accidentally ejected from an Embraer T-27 while waiting to take off at Pirassununga-Campo Fonetenelle, Brazil.

• 2011 – British Army Air Corps Apache attack helicopters from HMS Ocean destroy several Libyan government targets near the Brega-Ajdabiya front line, including ammunition bunkers and radar installations. French Gazelles hit numerous targets around Brega in preparation for an expected rebel ground offensive.^[5][6]

• 2009 – A Hellenic Air Force Lockheed Martin F-16C Block 50S Fighting Falcon, 93-1059, '059', of the 347 Fighter Squadron based at Nea Anchialos Airforce Base crashes near the village of Michalitsi part of the Tzoumerka National Park, Ioannina, Greece. The aircraft flying with another F-16 from the 111th Combat Wing suffered a bird strike and engine failure forced the pilot to successfully eject.

• 1996 – First successful launch of the Ariane 5

• 1991 – A student pilot died after ejecting from his North American T-2C Buckeye, BuNo 158877, 'F 807', of VT-4, CTW-6, based at NAS Pensacola, Florida, which impacted on an embankment on the south side of Berryhill Road extension, N of Pace, Florida about 1300 hrs.

• 1986 – In Operation Poomalai, five Indian Air Force Antonov An-32 (NATO reporting name “Cline”) transport aircraft airdrop supplies by parachute into the city of Jaffna, Sri Lanka, to aid Tamil Tiger rebels who have been besieged there by Sri Lankan government forces during the Sri Lankan Civil War. Five Mirage 2000 fighters escort the An-32 s, but the Indian aircraft meet no opposition.

• 1980 – First flight of the Mitsubishi F-15J

• 1975 – Sikorsky SH-3D Sea King, BuNo 152711, of HS-4, departs Naval Auxiliary Air Field Imperial Beach, California, at 1900 hours, en route to the Helicopter Offshore Training Area to conduct a scheduled night anti-submarine sonar training flight. Pilot-in-command is LT Leo S. Rolek, co-pilot is LTJG Charles D. Neville. Twenty minutes later, the crew reports their position and commences operations with four approaches to sonar hover and four night/low visibility and wind-line rescue patterns with hover trim practice until dusk. After sunset (1953 hours), the crew conducts four more approaches to sonar hovers while practising dip-to-dip navigation with the pilots alternating approaches. Complying with reporting in every half-hour, the practices proceed normally until 2133. With the sonar dome lowered down to 100 feet below the water's surface, the hover of the helicopter becomes unstable. The two sonar operators, AWH3 Brady W. Turner and AWH3 Peter C. Cassidy, sink the sonar dome deeper in the ocean, hoping the stability will improve and, for a brief moment, it works. But, then the sonar dome begins to pull Helo '740' downward to 30 feet above the waterline. The helicopter, pulled backwards, impacts the water, sinks quickly. The four crewmen all egress and are picked up by a Coast Guard Sikorsky HH-3F Pelican shortly before midnight and transported to the Naval Hospital at San Diego. Three crewmen are released from the hospital in the days that follow, but the pilot, who suffered a ruptured spleen, dies in hospital over three weeks later. This aircraft was the famed Helo '66' that had retrieved the Apollo 13 crew from the Pacific on 17 April 1970.

• 1974 – Construction of OV-101, the first Space Shuttle, begins. It later will be named Enterprise.

• 1972 – The USAF Thunderbirds suffer their first fatal crash at an air show during Transpo 72 at Dulles International Airport. Major Joe Howard flying Thunderbird 3, McDonnell Douglas F-4E-32-MC Phantom II, 66-0321, experiences a loss of power during a vertical manoeuver, and breaks out of the formation just after it completes a wedge roll and was ascending at ~2,500 feet AGL. The aircraft staggers and then descends in a flat attitude with little forward speed. Although Major Howard ejects as the aircraft falls back to earth from ~ 1,500 feet slightly nose low, and descends under a good C-9 canopy, winds blow him into the ascending fireball. The parachute melts and the pilot plummets 200 feet, sustaining fatal injuries in fall.

• 1969 – Mexicana Flight 704, a Boeing 727-64, crashes on approach to Monterrey, Mexico, killing all 79 people on board. Among the dead is Mexican tennis star Rafael Osuna.

• 1969 – 22-year-old man sneaks into wheel pod of a jet parked in Havana & survives 9-hr flight to Spain despite thin oxygen levels at 29,000 ft.

• 1968 – Lockheed A-12, 60-6932, Article 129, lost off of Okinawa during a functional check flight (FCF) following an engine change after deployment to Kadena Air Base in support of Operation Black Shield. Pilot Jack Weeks was killed while flying (KWF).:33One source gives date as 2 June.

• 1967 – In the Stockport air disaster, a British Midland Canadair C-4 Argonaut carrying passengers returning from Palma de Mallorca is on approach to Manchester Airport when an engine loses power because of a design failure in the aircraft's fuel system; 72 of 84 on board are killed.

• 1965 – First flight of the Nanchang Q-5

• 1965 – A USAF Fairchild C-119G Flying Boxcar is destroyed in crash in field near the turnpike in Sabattus, Maine after double engine failure. Crew bails out and is uninjured.

• 1961 – Lieutenant Colonel David F. "Snapper" McCallister, Jr. (Commander, 142d Fighter Bomber Squadron, Delaware Air National Guard) and Brigadier General William W. Spruance (Assistant Adjutant General for Air) were flying a Lockheed T-33A Shooting Star jet trainer out of Scott AFB, Illinois, when the aircraft lost power, and crashed. Colonel McCallister died and General Spruance received serious burn injuries. Milton Caniff is said to have based the character of Hotshot Charlie in the comic strip Terry and the Pirates on McCallister. He set a fighter record by flying his North American F-86 Sabre, "Cindee Lind 7th", 1,922 miles in 3 hours, 30 minutes to win the Air Force Association's Earl T. Ricks Memorial Trophy in 1956, given to Air Guard members for outstanding airmanship.

• 1959 – Max Conrad flies a Piper Comanche from Casablanca to New York, setting a new lightplane distance record of 7,683 miles (12,365 km).

• 1957 – World War II Japanese ace Maj. Teruhiko Kobayashi (1920–1957), flying with the reconstituted Japanese Self-Defense Air Force, is killed in the crash of a Lockheed T-33A Shooting Star during a training flight when he crashes in bad weather on approach to Hamamatsu Air Base. He ordered his back-seater to eject when the aircraft developed problems. He had shot down three Boeing B-29 Superfortress bombers and two Grumman F6F Hellcats with the 244th Sentai, although his widow claimed he had twice the number of Superfortress kills, a claim discounted by historian Takashi Sakurai.

• 1954 – Arthur Murray flies X-1 A rocket plane to record 27,000 m.

• 1948 – The Northwood mid-air collision happened on 4 July 1948 when a SAS DC-6, registration SE-BDA and a RAF Avro York, serial number MW248 collided over Northwood, London close to RAF Northolt. Thirty-nine passengers and crew of both aircraft died in Britain’s worst mid-air collision.

• 1948 – Philippine Airlines begins the first transpacific sleeper service, using Douglas DC-6 airliners between San Francisco, California, and Manila in the Philippine Islands.

• 1947 – A U.S. Marine Corps Vought F4U-4 Corsair crashes in the surf at Atlantic Beach, North Carolina during a VFW airshow, and pilot Lt. Gene Dial, of MCAS Cherry Point, North Carolina, walks some 15 feet to shore unhurt. The pilot, with four and a half years of service, said that he crashed once before during a carrier take-off.

• 1945 – Aichi E13A "Jake" floatplane, c/n 41116, of 634 Kokutai-Teisatsu, 302 Hikotai, crashed into the sea during night time search mission. Salvaged from waters off Kaseda city, Kagoshima prefecture on 22 August 1992, it is displayed in unrestored condition at the Kasedo Peace Museum, Kyūshū, Japan.

• 1944 – 34 Japanese aircraft attack an Allied task force of cruisers and destroyers as it approaches Biak, but inflict only slight damage. Four more make a torpedo strike overnight, but miss.

• 1943 – RAF Supermarine Spitfire Mk. Vc, AR512, of 312 (Czech) squadron based at Churchstanton in the Blackdown Hills hits a train while conducting a mock-attack near Bradford-on-Tone just west of Norton Fitzwarren. The roof of at least one carriage is ripped off and several passengers, mainly WRENs, are killed. The plane flies on before eventually crashing near Castle Cary. The pilot, F/O Jaroslav Cermak, dies and is buried in Taunton.

• 1942 – No. 417 (Fighter) Squadron arrived in Egypt to serve with the Desert Air Force.

• 1942 – The Battle of Midway begins with a predawn torpedo strike by U. S. Navy PBY Catalinas against Japanese ships, which damages an oiler. After sunrise, 108 aircraft from all four Japanese aircraft carriers – Akagi, Kaga, Hiryū, and Sōryū – carry out a destructive strike on Midway Atoll, shooting down 17 and severely damaging seven of the atoll’s 26 fighters. A series of Midway-based strikes by various types of aircraft against the Japanese carriers sees the combat debut of the Grumman TBF Avenger, but achieve no hits and suffer heavy losses. All three U. S. aircraft carriers – USS Enterprise (CV-6), USS Hornet (CV-8), and USS Yorktown (CV-5) – Launch strikes against the Japanese carriers; their 41 TBD Devastator torpedo bombers arrive first and achieve no hits, losing all but four of their number, but Enterprise’s and Yorktown’s SBD Dauntless dive bombers then arrive and inflict lethal damage on Akagi (which sinks on June 5) and Kaga and Soryu (which both sink later on June 4). A retaliatory strike by Hiryu fatally damages Yorktown (which sinks on June 7), but Enterprise and Yorktown dive bombers then fatally damage Hiryu (which sinks on June 5). The loss of all four of their carriers cause the Japanese to cancel the Midway operation and withdraw. It is widely considered to be the turning point of World War II in the Pacific.

• 1942 – 32 aircraft from Junyo and Ryūjō conduct another damaging strike against Dutch Harbor. Small strikes by U. S. Navy PBY Catalina flying boats and U. S. Army Air Forces bombers against the two Japanese aircraft carriers are ineffective.

• 1940 – The first Allied forces begin to withdraw from Norway, covered by aircraft from the British aircraft carrier HMS Ark Royal.

• 1940 – BOAC commences a twice-weekly service between England and Portugal, scheduled to connect with Pan Am flights from Lisbon to New York.

• 1935 – The Key brothers (Fred and Algene) fly twenty-seven days without landing, setting a world record for sustained flight in a Curtis Robin J-1, “Ole Miss. ”

• 1934 – The US Navy commissions its first purpose-built aircraft carrier, USS Ranger.

• 1932 – A Curtiss F9 C Sparrowhawk parasite fighter hooks onto the U. S. Navy dirigible USS Akron (ZRS-4) for the first time.

• 1932 – William G Swan, at Bader Field, Atlantic City NJ, makes the first Rocket-powered glider flight. He also carried some pieces of mail, which would undoubtedly qualify this flight as the first rocket air mail, as well. A second successful flight followed the next day.

• 1930 – Lt Apollo Soucek sets a new seaplane altitude record of 43,166 ft (13,157 ft) in a Wright XF3 W|

• 1927 – (4-6) With Charles A. Levine as his passenger, Clarence Duncan Chamberlin made a record nonstop transatlantic flight, in his monoplane Columbia, from Roosevelt Field, Long Island, New York, to Eisleben, Germany, a distance of 3,911 miles (6,294 km), in 42 hours and 31 min.

• 1925 – First flight of the Marinens Flyvebaatfabrikk M.F.9

• 1920 – The US Army Reorganization Act is passed, dashing hopes for an independent air arm like Britain's Royal Air Force.

• 1919 – The British offer Canada Imperial a Gift of 100 aircraft with support equipment.

• 1915 – First flight of the Marinens Flyvebaatfabrikk M.F.1

• 1914 – First fatal British seaplane accident kills Lt. T. S. Cresswell and Cmdr. A. Rice of the Royal Navy. While ascending from the Calshot Air Station, the Short S.128 they are flying passes over motorboat on Southampton Water where Short's test pilot Gordon Bell and Lt. Spencer Grey are watching flight. At height of just over 200 feet, seaplane appears to break up and plummets into sea, killing both occupants. Some witnesses say that they believed that the seaplane stalled and that the wings folded up as structural limits were exceeded.

• 1784 – First untethered balloon flight by a woman. Madamne Elizabeth Thible, a French opera singer, in order to entertain Gustav III of Sweden in Lyon.

• 1783 – In Annonay, France, the Montgolfier brothers, Joseph-Michel and Jacques-Etienne, give the first public demonstration of their hot-air balloon by sending up a large model made of linen lined with paper.