By Marina Malenic

PARIS–The F-35 Lightning II Joint Strike Fighter program could experience a doubling of its current expected sales as fourth-generation fighter fleets worldwide enter the end of their service life, the F-35 program manager said yesterday.

“If I take a look at the entire inventory of the world–those that are flying F-16, the F-15 and other fourth-generation aircraft–as those airplanes age out, I believe my airplane will be competitive,” said Marine Corps Brig. Gen. David Heinz.

Heinz said the F-35 could replace 13 different fighter aircraft models around the world.

Sales of the Lockheed Martin [LMT]-built fighter jet to eight U.S. partner countries–Australia, Canada, Denmark, Italy, the Netherlands, Norway, Turkey and the United Kingdom–are already expected to top 3,000, according to company executives. Discussions with, Israel, Singapore and Spain are also continuing. Heinz also named Finland, Japan and South Korea as countries that have expressed an interest in receiving more information about the airplane.

Boeing [BA] has been promoting the F/A-18 Super Hornet and a stealthier version of its F-15 Eagle as an alternative for international customers that don’t want to spend $80 million per aircraft. The F/A-18 sells for starting at under $55 million.

Heinz said the F-35 will be more affordable than its competitors because of the high production rates expected later in the program.

“The partnership is strong, the program is stable and the value proposition on which this program was founded remains intact,” said Heinz.

The Pentagon plans to purchase 1,763 F-35s for the Air Force, Marine Corps and Navy. Under that scheme, the jets will cost approximately $80 million apiece and, Heinz said, cost will come down as production rates ramp up. Lockheed Martin is currently producing one aircraft per month but expects that number to go up to one per day by 2014.

In April, Defense Secretary Robert Gates said he wanted to end production of the Lockheed Martin-built F-22 Raptor at 187 airplanes in the U.S. fleet in order to free up more funding for F-35s. Gates said he wanted to eventually boost funding for the F-35 by $4.4 billion to $11.2 billion over the next five years, to bring the fleet to 513 jets. The plan includes a purchase of 30 jets in fiscal 2010, compared to the 14 scheduled to be bought in 2009.

Richard Aboulafia, an analyst with the Teal Group in Fairfax, Va., said the total F-35 export market could exceed 2,000 airplanes, but several technological and market factors will affect the final number. First and foremost, he said, technical maturation of unmanned combat air vehicle alternatives could drive the need for manned fighters down.