The Pentagon Friday awarded Lockheed Martin a contract-the military's richest ever-to build the Joint Strike Fighter aircraft. Lockheed Martin bested the Boeing Co. in a closely watched competition for the contract, worth $200 billion. The Bethesda, Md., contractor will produce 3,002 planes for the Air Force, Navy, Marine Corps and Great Britain beginning in 2008 and ending in 2040. Additional sales to other U.S. allies could enhance the value of the contract for the new fighter, which will be known as the F-35, to more than $400 billion over the next three decades. The planes will cost the United States and Britain between $40 million and $50 million apiece and replace Air Force F-16s and A-10s, Navy F/A-18s, Marine Corps AV-8B Harriers and British Royal Navy and Air Force fighters. Air Force Secretary James Roche said both contractors offered "very good" models, but Lockheed Martin "emerged continuously as a strong winner" throughout the various stages of the competition. Since 1996, the two contractors have been developing prototypes of the radar-evading fighter that could not only take off from air fields, but also land vertically and be launched from aircraft carriers. Pete Aldridge, the Pentagon's acquisition chief, said Defense "seriously considered" splitting the contract between the two companies, but ultimately decided that awarding the work to one contractor was its best option. Lockheed Martin could choose to hire Boeing as a subcontractor for Joint Strike Fighter work, he added. Defense analysts said Boeing will be able to better sustain the loss of the contract than Lockheed Martin would have because it has a strong line of commercial aircraft and is a leader in the development of unmanned aerial vehicles. Lockheed Martin officials have said that work on the new aircraft could add as many as 9,000 jobs at its facility in Fort Worth, Texas.