Lockheed Martin Corp's F-22 "Raptor" fighter jet, widely considered the world's most advanced, is set to streak through a milestone performance here on Monday for a U.S. warplane that unlike most others remains off limits for export.

The 60th Farnborough event will mark the radar-evading jet's debut at an overseas air show and is due to see it demonstrate a manoeuvre called a "tail-slide", in which the pilot shoots nearly straight up, then lets the sleek, 43,340-pound jet drop without stalling.

It is a display made possible by the thrust of dual engines built by Pratt & Whitney, part of United Technologies.

The single-seat aircraft is capable of twice the speed of sound.

Pilot Major Paul 'Max' Moga from the U.S. Air Force 27th Fighter Squadron is also scheduled to open the weapons-bay doors after pointing the aircraft's belly at spectators, showing where bombs and missiles would be stored.

Unlike most fighters, no weapons are carried externally on the Raptor, to make it harder to detect on radar screens.

Crossing the Atlantic to get here was itself a first for the aircraft, deployed last year to Kadena Air Base on the Japanese island of Okinawa, the hub of U.S. air power in the Pacific.

Japan, Israel and Australia have shown interest in buying the F-22 if the U.S. Congress were to lift the export ban enacted 10 years ago, partly to prevent the spread of U.S. technological knowhow and partly to avoid regional arms races.

Also of concern is protecting the market for Lockheed Martin's F-35 Joint Strike Fighter, a family of radar-evading fighters being developed by the United States with eight other countries.

The F-22 production line is about to enter the final 12 months of a 3-year, 60-aircraft purchase by the U.S. Air Force.

U.S. Air Force officials have said they need 381 Raptors to meet their requirements. But the Pentagon's fiscal 2009 budget request, unveiled February 4, made no provision for any beyond an already approved 183 jets.

This left a decision to the U.S. president to be elected November 4 on whether to keep open or close the F-22 production line. If shut, it could be for good, given the high cost of resuming output.

Primarily an air superiority fighter, the F-22 also has capabilities for ground attack, electronic warfare and intelligence gathering.

The United States began operating it in December 2005, 20 years after it was conceived to defeat Soviet warplanes in air-to-air combat over Europe.

F-22s go for $142 million apiece not including development costs, according to the Air Force.

"The F-22 cannot be matched by any known or projected fighter aircraft," according to an Air Force release that calls it "an exponential leap in warfighting capabilities."

Capt. Michael Andrews, an Air Force spokesman at the Pentagon, said in an emailed statement that the service "has no intention of pursuing international sales or entertaining foreign agreements without Congressional approval."

Robert Stevens, Lockheed Martin's chief executive, told reporters Sunday night that he was unaware of any "discussion", by implication among U.S. decision-makers, about repealing the prohibition on F-22 exports from the United States.

In the absence of funding for "long lead" materials used in the manufacturing process, Lockheed "probably" will have to notify suppliers toward the end of this year about the program's fate, Stevens said.