to be known as the F-55, as well as an upgrade to its Lockheed Martin F-22 Raptor called the F-22 Super, U.S. President Donald Trump said on Thursday. Trump was speaking at a meeting of business leaders including the heads of Boeing and GE Aerospace in Doha, a day after announcing a string of business deals including an order from Qatar for 160 Boeing commercial jets.

Trump referred to the proposed F-55 as both an upgrade to the Lockheed Martin F-35 and a separate new development.

He also highlighted the role of a new air dominance platform called the F-47, recently awarded to Boeing, and said the United States was simultaneously looking at upgrading the stealth fighter it is designed to replace, the F-22.

"We're going to do an F-55 and - I think, if we get the right price, we have to get the right price - that'll be two engines and a super upgrade on the F-35, and then we're going to do the F-22," Trump said.

"I think the most beautiful fighter jet in the world is the F-22 but we're going to do an F-22 Super and it'll be a very modern version of the F-22 fighter jet." Trump's comments came weeks after he awarded Boeing the contract for the F-47 - a replacement for the F-22 stealth fighter featuring a crewed aircraft flanked by drones and seen as America's most advanced or sixth-generation fighter. Analysts said it was not immediately clear how Trump's list fitted into a jigsaw of known programmes or spending plans.

Agency Partners aerospace analyst Nick Cunningham said the F-55 may refer to the F/A-XX programme, intended to replace the U.S. Navy's Boeing F/A-18 Super Hornet fleet during the 2030s.

The Navy and Congress are battling with the administration to keep the plans moving forward, Reuters reported on Wednesday.

Any significant upgrade to the out-of-production F-22 would be costly, while Trump's reference to two engines implies the F-55 would not be closely related to the single-engined F-35, he said.

Lockheed Martin is in the midst of a delayed software upgrade for the F-35 to boost displays and processing power.

CEO James Taiclet also told analysts last month that Lockheed was looking at ways of applying co-funded technology that was developed for its losing bid for the F-47 contract to the F-35, delivering 80% of the capability for half the cost.