WASHINGTON, March 25 (Reuters) - The U.S. Navy is

expected to announce this week who will build its

next-generation carrier-based stealth fighter - a program worth

hundreds of billions over its lifetime and a key part of plans

to confront China, people familiar with the decision said.

The F/A-XX program is one of several advanced capabilities

the U.S. military is developing to counter China's growing

assertiveness in the Indo-Pacific region. The contract would be

worth single-digit billions of dollars in the short term, and

potentially hundreds of billions over the decades it is expected

to run.

The Navy will choose one winner for the engineering and

manufacturing development (EMD) phase - a significant milestone

for the F/A-XX, which is meant to replace the Navy's F/A-18E/F

Super Hornet fleet.

The new jet is expected to feature advanced stealth

capabilities, improved range and endurance, and the ability to

integrate with both uncrewed combat aircraft and the Navy's

carrier-based air defense systems.

The U.S. Navy did not respond to a request for comment. The

new Secretary of the Navy, John Phelan, was confirmed on Monday.

The competition has been intense, with Boeing Co ( BA ),

Lockheed Martin ( LMT ), and Northrop Grumman Corp ( NOC )

submitting detailed proposals and prototypes for evaluation.

Boeing ( BA ), hit hard by a recent labor strike, engineering

layoffs, problems with its Starliner capsule and the troubled

KC-46 tanker program, got a recent shot in the arm when it won

the Air Force's F-47 contract. It also produces the MQ-25

carrier-based uncrewed refueling aircraft.

Taking on two fighter jet programs may offer economies of

scale if the company can make larger purchases of raw materials

and share technology between the aircraft.

Northrop Grumman ( NOC ) has a strong track record of producing

innovative aircraft, including the B-2 and B-21 stealth bombers.

Lockheed Martin ( LMT ) was initially seen as a strong contender,

but the company struggled to meet the Navy's specific

requirements, including the need for a more advanced radar

system and improved carrier landing capabilities. Reuters

reported on March 4 that Lockheed had been eliminated from the

competition, but the Navy has not made a formal announcement.

The first production jets are expected to enter service in

the 2030s, while F/A-18s are expected to remain in service into

the 2040s.