Known as the Low-Boom Flight Demonstrator (LBFD), this X-plane is scheduled to make its first test flight as early as 2021 and "would open a new market for U.S. companies to build faster commercial airliners, creating jobs and cutting cross-country flight times in half," the White House budget request states. The goal of supersonic aircraft like LBFD is to make commercial airplanes that can fly faster than the speed of sound without generating a loud and obnoxious sonic boom, an ear-splitting noise associated with shock waves generated by an aircraft as it breaks the sound barrier "Future supersonic aircraft seeking...