A new concept aircraft from Lockheed Martin could pave the way for supersonic flights over land by shushing the sonic booms created by the planes. The new design would rely upon a so-called "'inverted-V' engine-under wing configuration, where the engines sit atop the wings rather than beneath," according to a statement by NASA officials. The U.S. and many other nations currently ban overland supersonic flights because of the loud boom and rattle effect.