NASA's X-34A scramjet broke every speed record in the book by traveling at nearly Mach 10, or about 7,000 miles per hour. Scramjets have been studied and under development for years, but they were mostly theoretical--no one was really sure they would work.
Scramjets, in addition to some military uses, offer an alternative to expensive and heavy chemical rockets for getting into space. One more signal for the emerging Space Economy.