I'm excited about this one. United Airlines announced Thursday that it hopes to fly passengers on a new supersonic jetliner by 2029— resurrecting high-speed flights more than two decades after the Concorde was grounded.

The planes will zip travelers around the globe in half the time of traditional flights, for the price of a current first-class ticket. That's New York to London in 3½ hours and San Francisco to Tokyo in just six hours, for about $5,000 to $7,000.

Of course, Jalopnik notes that the company that United partnered with, Boom Supersonic, isn't exactly a household name and hasn't actually built this lovely machine. Boom Supersonic has only built a proof-of-concept plane called the XB-1, which is much smaller and hasn't even gotten off the ground yet.

Some industry observers are skeptical though about the supersonic market. One aviation consultant told the Wall Street Journal that there are only a handful of routes with enough traffic to support enough full-fare premium passengers, and not enough to justify the development and production of a supersonic jetliner.