San Francisco to Tokyo in 6 hours? United Airlines to bring back supersonic flying with Boom deal

United Airlines said on Thursday would buy ultra-fast jets from Denver-based aerospace company Boom Supersonic, bringing back supersonic passenger travel which died out with the retirement of the Anglo-French Concorde in 2003.

United Airlines announced plans Thursday to buy 15 planes from airline startup Boom Supersonic in a move that could revive the high-speed form of air travel after the Concorde was wound down in 2003. Under the commercial agreement, United would purchase Boom's "Overture" aircraft once the planes meet "United's demanding safety, operating and sustainability requirements" with an aim to start passenger travel in 2029, the companies said in a joint press release. The announcement represents a potential comeback to a once heavily-touted method of travel, although some analysts expressed skepticism, particularly over the relatively speedy timeframe.