WASHINGTON, March 20 (Reuters) - The Pentagon is set to

announce its decision on the Next Generation Air Dominance

program as soon as Friday, despite earlier concerns about budget

constraints and shifting priorities, sources briefed on the plan

said.

Lockheed Martin Corp ( LMT ), Boeing Co ( BA ), are

competing for the Next Generation Air Dominance (NGAD) program,

which will replace Lockheed's F-22 Raptor with a fighter built

to battle alongside drones.