The Boeing X-46 was a proposed unmanned combat air vehicle (UCAV) that was to be developed in conjunction with the U.S. Navy and DARPA as a naval carrier-based variant of the Boeing X-45 UCAV being developed for the U.S. Air Force. Two contracts for technology demonstrators were awarded in June 2000, to Boeing for the X-46A and to Northrop Grumman for the X-47A.
However, in April 2003, the Air Force and the Navy efforts were formally combined under the joint DARPA/USAF/Navy J-UCAV program, later renamed J-UCAS (Joint Unmanned Combat Air Systems), and the X-46 program was terminated as redundant.
The J-UCAS program was later terminated.
A Navy-only N-UCAS demonstrator program started in the summer of 2006. Boeing will use material developed for the X-46 and X-45 to propose the X-45N as a naval UCAV demonstrator.