Sonic boom or bust? Dreams of super-fast jet travel revival face headwinds

Supersonic passenger travel, which died out with the Concorde's demise in 2003, will make a comeback by the mid-2020s if 3 entrepreneurial US-based companies can make jets quiet and efficient enough to win over buyers and fliers. Japan Airlines and Virgin Group are backing 1 of the 3 US supersonic projects, Boom Technology which plans a 55-seat all business class jet. "This is more about engines and economics than it is about airframes," one analyst said of the challenges of a supersonic revival. To make the project economics stack up the engines need to be far more fuel efficient and less noisy than those used by Concorde or fighter jets. That has proven tough to engineer, especially at higher speeds like the Concorde's Mach 2, which halved the travel time from London to New York to 3.5 hours. <br/>