Flight airspeed record

An air speed record is the highest airspeed attained by an aircraft of a particular class. The rules for all official aviation records are defined by Fédération Aéronautique Internationale (FAI), which also ratifies any claims. Speed records are divided into multiple classes with sub-divisions. There are three classes of aircraft: landplanes, seaplanes, and amphibians; then within these classes, there are records for aircraft in a number of weight categories. There are still further subdivisions for piston-engined, turbojet, turboprop, and rocket-engined aircraft. Within each of these groups, records are defined for speed over a straight course and for closed circuits of various sizes carrying various payloads.

Timeline
Gray text indicates unofficial records, including unconfirmed or unpublicized war secrets.

Official records versus unofficial
The Lockheed SR-71 Blackbird holds the official Air Speed Record for a crewed airbreathing jet engine aircraft with a speed of 3530 km/h. The record was set on 28 July 1976 by Eldon W. Joersz and George T. Morgan Jr. near Beale Air Force Base, California, USA. It was able to take off and land unassisted on conventional runways. SR-71 pilot Brian Shul claimed in The Untouchables that he flew in excess of Mach 3.5 on 15 April 1986, over Libya, in order to avoid a missile.

Although the official record for fastest piston-engined aeroplane in level flight was held by a Grumman F8F Bearcat, the Rare Bear, with a speed of 528.31 mph, the unofficial record for fastest piston-engined aeroplane in level flight is held by a British Hawker Sea Fury at 547 mph. Both were demilitarised and modified fighters, while the fastest stock (original, factory-built) piston-engined aeroplane was unofficially the Supermarine Spiteful F Mk 16, which "achieved a speed of 494m.p.h. at 28,500ft during official tests at Boscombe Down" in level flight. The unofficial record for fastest piston-engined aeroplane (not in level flight) is held by a Supermarine Spitfire Mk.XIX, which was calculated to have achieved a speed of 690 mph in a dive on 5 February 1952.

The last new speed record ratified before the outbreak of World War II was set on 26 April 1939 with a Me 209 V1, at 755 km/h. The chaos and secrecy of World War II meant that new speed breakthroughs were neither publicized nor ratified. In October 1941, an unofficial speed record of 1004 km/h was secretly set by a Messerschmitt Me 163A "V4" rocket aircraft. Continued research during the war extended the secret, unofficial speed record to 1130 km/h by July 1944, achieved by a Messerschmitt Me 163B "V18". The first new official record in the post-war period was achieved by a Gloster Meteor F Mk.4 in November 1945, at 606 mph. The first aircraft to exceed the unofficial October 1941 record of the Me 163A V4 was the Douglas D-558-1 Skystreak, which achieved 641 mph in August 1947. The July 1944 unofficial record of the Me 163B V18 was officially surpassed in November 1947, when Chuck Yeager flew the Bell X-1 to 891 mph.

The official speed record for a seaplane moved by piston engine is 709.209 km/h, which attained on 24 October 1934, by Francesco Agello in the Macchi-Castoldi M.C.72 seaplane ("idrocorsa") and it remains the current record. It was equipped with the Fiat AS.6 engine (version 1934) developing a power of 3100 hp at 3,300 rpm, with coaxial counter-rotating propellers. The original record holding Macchi-Castoldi M.C.72 MM.181 seaplane is at the Air Force Museum at Vigna di Valle in Italy.

Other air speed records
Flying between any two airports allow a large number of combinations, so setting a speed record ("speed over a recognised course") is fairly easy with an ordinary aircraft, although there are many administrative requirements for recognition.