If speed is your thing and you have some loose change to spare, then an upcoming auction may have just the item for you. UK-based RM Auctions is offering a Kholod hypersonic rocket as an upcoming lot. The Kholod is the fastest machine to have ever flown within the Earth's atmosphere.
The rocket on sale is one of eight that were built as part of a US$95 million partnership between NASA and the Russian Institute for New Propellants (CIAM). The program sought to develop a hypersonic machine using pioneering propulsion technology.
The resulting Kholod rockets, or "scramjets," were fueled by cryogenically cooled liquid hydrogen and were capable of traveling at Mach 6.47 (4,310 mph / 6,936 km/h). According to RM Auctions, the first Kholod rocket was tested in Kazakhstan in November 1991, reaching an altitude of 35 km (22 mi).
Over the next 10 years, the Kholod was the world record holder for outright atmospheric speed and it is still the fastest machine to have traveled within Earth’s atmosphere.
A total of nine Kholod rockets were produced, of which five were destroyed during tests. Of the remaining four which returned to Earth, only three remain in existence. This is the first time that a Kholod rocket has been made available to the public to buy.
The Kholod will be auctioned alongside a number of cars on September 8th.
Source: RM Auctions
So it claims the record until 2001 and the X-43 took the record in 2001 from the X-15A-2
And a re-entry is hardly self-powered flight.
1) Re: the X-43A, read the seventh paragraph of the link I included: "Following the successful second flight, a third and final test of the X-43A on November 16, 2004, achieved a new record speed of Mach 9.68 (6,600 mph)."
2) Re: your 10-year (1991-2001) argument, what you say is correct, but that's not what the title of the Gizmag article states ("For sale: The fastest machine **ever** flown within the Earth’s atmosphere")
3) Re: STS re-entry, where in the Gizmag article does it refer to self-powered flight? The claim made in the article is that the Kholod is "the fastest machine to have traveled within Earth’s atmosphere."