US President Donald Trump has announced Boeing will build the Air Force’s future fighter jet, which the Pentagon says will have stealth and penetration capabilities that far exceed those of its current fleet and is essential in a potential conflict with China.

Known as Next Generation Air Dominance, or NGAD, the manned jet will serve as quarterback to a fleet of future drone aircraft designed to be able to penetrate the air defences of China and any other potential foes. The initial contract to proceed with production on a version for the Air Force is worth an estimated $US20 billion ($AU31 billion).

The 47th president, who announced the award at the White House with Defence Secretary Pete Hegseth and Air Force leadership, said with a grin that the new fighter would be named the F-47.

General David Allvin, chief of staff of the Air Force, said, “We’re going to write the next generation of modern aerial warfare with this.” And Hegseth said the future fleet “sends a very clear, direct message to our allies that we’re not going anywhere.”

Critics have questioned the cost and the necessity of the program as the Pentagon is still struggling to fully produce its current most advanced jet, the F-35, which is expected to cost taxpayers more than $AU2.8 trillion over its lifespan.

In addition, the Pentagon’s future stealth bomber, the B-21 Raider, will have many of the same cutting-edge technologies in advanced materials, AI, propulsion and stealth.

More than 1100 F-35s have already been built for the US and multiple international partners.

A fleet of about 100 future B-21 stealth bombers at an estimated total cost of at least $207 billion is also planned. The first B-21 aircraft are now in test flights.

With evolving drone and space warfare likely to be the centre of any fight with China, Dan Grazier, a military procurement analyst, questions whether “another exquisite manned fighter jet really is the right platform going forward.” Grazier, director of the national security reform program at the Stimson Center, said $31 billion is “just seed money. The total costs coming down the road will be hundreds of billions of dollars.”

Few details of what the new NGAD fighter would look like have been public, although Trump said early versions have been conducting test flights for the last five years. Renderings by both Lockheed Martin and Boeing have highlighted a flat, tail-less aircraft with a sharp nose.

The selection of Boeing, which has faced intense pressure from Trump over cost overruns and program delays on Air Force One, came after an independent analysis by the Air Force, an official said on the condition of anonymity to provide additional details on the selection. The Boeing offer was still determined to be the “best overall value to the government,” the official said.

The Air Force has not specified how many aircraft will be produced. In a statement, however, Allvin said there would be more F-47s produced than F-22s, the advanced fighter jet it’s replacing. There are now about 180 F-22 fighter jets in service.

A separate Navy contract for its version of the NGAD fighter is still under competition between Northrop Grumman and Boeing.

Last year, the Biden administration’s Air Force secretary, Frank Kendall, ordered a pause on the NGAD program to review if the aircraft was still needed or if the program, which was first designed in 2018, needed to be modified to reflect the past few years of warfighting advances.

That review by think tanks and academia examined what conflict with China would look like with NGAD and then without it — and determined that NGAD was still needed. Kendall then left the decision on which firm would build the fighter jet to the incoming Trump administration, a defence official said, speaking on the condition of anonymity to provide details on the decision-making.

NGAD will bring “an entirely different level of low observability,” the official said. It will also have a much longer range than the F-35 or other current fighter jets, so it will require less refueling. A future unmanned version of NGAD also is planned as the Pentagon improves the AI for the aircraft, the official said.