The Indian Air Force (IAF) has announced it will retire its fleet of MiG 25s, Cold War-era spyplanes, previously shrouded in secrecy.
The Indian MiG 25s were a jealously guarded secret
A spokesman said the last of the IAF's four surviving MiG-25s will be phased out of service on 1 May.
The MiGs, capable of flying at over three times the speed of sound, were bought from the USSR in 1981.
"It will be a nostalgic event and a flypast will be held," Air Vice Marshal S Mukherjee said.
He said the aircraft would be shown at various installations after they had been retired.
'Darned good machine'
India originally bought 10 of the MiGs from the Soviet Union and nicknamed the 20-ton reconnaissance planes Garuda after the mythical Hindu eagle king.
The aircraft were based at an undisclosed location.
"It was a darned good machine but even today we are not permitted to speak of the daredevilry these stratospheric planes have been used for," an unnamed MiG 25 pilot was quoted by news agency AFP.
"All I can say is that I more than once hit Seven Plus (70,000 feet) with them," he said.
The MiG 25, which was built in both reconnaissance and interceptor versions, is the fastest combat aircraft ever built, apart from the US Lockheed SR-71 Blackbird spyplane.
It was designed in the late 1960s to beat the US Air Force's XB-70, a supersonic bomber which never entered service. The Pentagon's misplaced belief that the MiG was a highly-agile dogfighter spurred the development of the US F-15 and F-16 fighters.
In 1976, a Soviet pilot defected to Japan in a MiG 25. The US subsequently stripped the aircraft and studied it before returning it to the USSR.
They found the MiG was a heavy but powerful aircraft with a 1950s-vintage radar capable of burning through protective electronic countermeasures.
MiG 25s were later exported to several nations, including Algeria, Syria and Iraq.