The Next-Generation Bomber (NGB; formerly called the 2018 Bomber) was originally a program to develop a new medium bomber for the United States Air Force. The NGB was originally projected to enter service around 2018 as a stealthy, subsonic, medium-range, medium payload bomber to supplement and possibly—to a limited degree—replace the U.S. Air Force's aging bomber fleet (B-52 Stratofortress and B-1 Lancer). The NGB program was superseded by the Long-Range Strike-B (LRS-B) heavy bomber program.