SST Redux: Are The New Supersonic Jets Friendlier To The Planet? — P. Barnes, Midlothian, TX Nearly 20 years have passed since the last flight of the Concorde, the first supersonic passenger-carrying commercial airplane (or supersonic transport, SST). The aircraft cruised the Queen of England and the ultra-wealthy across the seas at Mach 2 speed, or 1,350 mph, while soaring at an altitude of 60,000 feet. In 1996, the Concorde achieved its fastest flight from New York to London in under three hours. Now a new wave of supersonic flight may be on the horizon with the recent partnership between United Airlines and Denver-based Boom Supersonic. In June 2021, United Airlines announced plans to purchase 15 of Boom Supersonic’s first commercial supersonic jet, the Overture. Boom plans to engineer the Overture to fly up to 88 passengers at a speed of Mach 1.7, or 1,300 mph, at 60,000 feet. Most flight times will be cut nearly in half: Traveling from Paris to Montreal will only take three hours and 45 minutes instead of the usual eight and a half hours; a trip from San Francisco to Tokyo take just six hours rather than the usual 10 hours and 15 minutes.