Which is the fastest airplane in the world?

Answer 1

The fastest airplane was the North American X-15 (7274 km/h) but it is not cathegorized as a airplane record because it didn't took of by itself, instead it was launched from a B 52, the fastest airplane other than the X-15 is the Lockheed SR-71 blackbird which was used as a recon aircraft by the USAF, it reached mach 3

The fastest airplane in the world is the SR-71 Blackbird and the fastest commercial aircraft is the out-of-commission British/French Concorde (READ BELOW).

Probably a jet. No one can know for sure.

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*Fastest manned Airbreathing Jet-engined (Non rocket powered) aircraft:

SR-71 Blackbird - 2.200 mph - 3.500 km/h. (Mach 3.2)

*Fastest manned rocket propelled aircraft:

X-15 - 4.500 mph - 7.200 km/h (Mach 6.7)

*Fastest Unmanned Air breathing Aircraft

X-43 - 7.500 mph - 12.000 (Mach 9.8)

*Fastest space vehicle:

Apollo 10 Saturn V (Saturn Five) at 25.000 mph - 40.000km/h. <--- This is the fastest un-classified speed attained by humans.

However, in space, it is possible to break this record with relative ease since there is (almost) no drag, but only if you can carry enough fuel.

I hope I have sufficiently answered your question.

IT--
North American X15 which set many world record
The fastest airplane ever that made into production was the American Lockheed-Martin SR-71 Blackbird, capable of in excess of MACH 3 at up to 85,000 feet. The fastest recorded speed for the Blackbird was over 1,905 knots or 2,193 mph in 1976.

The fastest recorded manned airplane flight was Robert's M. White flight in Bell X-15, on 9th November, 1961. He pushed this rocket-powered protoype to 4092mph on 19 miles above the surface, what equals to Mach 6.72.
The fastest manned jet engined aircraft is the SR-71 "Blackbird", at 1905.81 knots (2194 mph/3530 kmph).

The aircraft holding the record for fastest manned flight is the X-15 rocket plane which attained a speed of Mach 6.7 (4519 mph/7,273 km/h) on October 3, 1967 however this aircraft is no longer in service with either NASA or the US Airforce.

The fastest unmanned aircraft is the experimental X-43A, at Mach 9.86 (7546 mph/12144 kmph).

Please see the related links.
North American X15

AnswerThunderbird 1 @ 15000 mph Mach 22.6

http://en.wikipedia.org/wiki/Thunderbirds_machines#Thunderbird_1
If im not mistaken, it would be the blackbird stealth plane, which im pretty sure can go more than 3 times the speed of sound.