Stealth is integral to the design of the F-35. A low radar signature means the plane is harder for enemies to see, and so can get closer to targets before it’s in danger. Keeping that stealth body while developing three version: the F-35A for the Air Force, the F-35B with short takeoff and vertical landing capability for the Marine Corps, and the F-35C for the Navy (rugged enough to land on aircraft carriers) meant the planes had to make some compromises in design, like small internal bomb bays for stealth missions. In the 20 years from the start of the development of the F-35, stealth remained a consistent part of the program, one deemed essential by the Air Force and a shared bonus for the Navy and Marines, as well as the foreign allies who are buying the F-35.