The new era of supersonic travel may end before it even begins

Companies competing to build a successor to the Concorde may find that the biggest hurdle isn’t technology or economics, but the hefty carbon footprint that’s the result of such eye-watering speeds -- especially with electric airliners that may soon be within reach. Driven by mounting public and political concerns about aviation emissions, the new-found environmental zeal of manufacturers threatens to make start-ups intent on breaking the sound barrier look like relics from a greedier age that spared little thought for the environment. That’s despite advances in aerodynamic design, materials and propulsion. Those concerns were on display at last week’s Paris Air Show, where Boom Technology, which is working to introduce a 75-seat, Mach 2.2 jetliner, went out of its way to assert the plane’s green credentials. <br/>