Ever imagined how a 5-hour flight to New York would feel like Or if it would even be feasible Well, we don't know about Delhi to New York yet but Londoners could be taking three-hour flights to New York and vice-versa. A couple of days ago, United Airlines inked a 15-plane deal with Boom Supersonic, whose supersonic jets fly at twice the speed of the best aircraft operating today. This also means that San Francisco to Tokyo will mean just six hours of flying time, from the current 11-hours duration.