The US Navy did not commit to practical UCAV efforts until mid-2000, when the service awarded contracts of US$2 million each to Boeing and Northrop Grumman for a 15-month concept-exploration program.

The Navy was also interested in using their UCAVs for reconnaissance missions, penetrating protected airspace to identify targets for the attack waves.

The Navy went on to give Northrop Grumman a contract for a naval UCAV demonstrator with the designation of "X-47A Pegasus", in early 2001.

The X-47A is powered by a single Pratt & Whitney Canada JT15D-5C small high-bypass turbofan engine with 3,190 lbf (14.2 kN) thrust.

However, to keep costs low, the engine exhaust is a simple cylindrical tailpipe, with no provisions for reducing radar or infrared signature.

The X-47A was rolled out on 30 July 2001 and performed its first flight on 23 February 2003 at the Naval Air Warfare Center at China Lake, California.