Panetta hails F-35 jet as key for UK, U.S. Wed Jul 18, 2012 12:26pm EDT (Reuters) - U.S. Defense Secretary Leon Panetta said Wednesday that Lockheed Martin Corp's F-35 Joint Strike Fighter aircraft represents the "future of tactical aviation" for U.S. and British forces, as Britain prepares to take delivery of its first test aircraft. The scheduled delivery Thursday at Lockheed's Fort Worth, Texas, production plant is an indication of considerable strides in the program, particularly in the past year, Panetta told a Pentagon press conference alongside Philip Hammond, his British counterpart. The radar-evading F-35 is the Pentagon's costliest arms purchase, expected to top $396 billion for 2,443 aircraft in three models through the mid-2030s. It is being built for the U.S. Air Force, Navy and Marine Corps and eight co-development partners -- Britain, Italy, Turkey, Canada, Australia, Denmark, Norway and the Netherlands. Israel and Japan also are buying the F-35 and others have shown interest. The Defense Department this year postponed production of 179 jets until after 2017, providing more time for development and testing in an effort to curb costly retrofits. The program's latest restructuring, the third such revamp, added 33 months and $7.9 billion to the development plan. The Pentagon is fully confident that it will be able to meet its "full commitment" to the program, Panetta said, despite a flattening of its overall spending amid U.S. deficit-reduction requirements. "The F-35 represents, I believe, the future of tactical aviation for both of our armed services," he said. It will make it possible to "effectively control the skies as we confront the enemies of tomorrow." The continued commitment to the program will also further solidify the U.S.-British alliance, Panetta said, handing Hammond a small-scale model of the new fighter. Lockheed Martin, the Pentagon's No. 1 supplier by sales, has said that international demand may help offset slower U.S. production rates. The company expects the F-35 to account for about 20 percent of revenue once full production begins at a date to be determined in coming years. Reporting By Jim Wolf; Editing by Gerald E. McCormick and Sofina Mirza-Reid