You might be able to fly to Europe in half the time on United Airlines, but you have to wait until 2029

Get yourself to Europe or Asia in the amount of time it would take to travel to, say, Cleveland.

That’s the aim of United Airlines, which today announced it’s buying 15 of Boom Supersonic’s Overture airliners, which could mean Newark, New Jersey, to London in three and a half hours, Newark to Frankfurt in four hours, and San Francisco to Tokyo in six hours.

The plane, which is still in development, will supposedly be able to fly at speeds of Mach 1.7. That’s double the speed of today’s fastest air passenger carriers, according to the Chicago-based airline, which says this could almost halve flight time for 500-plus destinations.

If things go well, United has the option to buy another 35 of the aircraft.

Don’t go hunting for your frequent-flyer number just yet, though. The new planes are not expected to be ready for passenger flights until 2029.

“Once operational, Overture is expected to be the first large commercial aircraft to be net-zero carbon from day one, optimized to run on 100% sustainable aviation fuel,” United and Denver-based Boom Supersonic said in a written statement.

The most iconic supersonic passenger plane was the Concorde, which started service in 1976 and ceased flying in 2003. It shuttled the wealthy and famous across the Atlantic for British Airways and Air France.