(Adds comments from lawmakers, former Pentagon official)
ST. LOUIS, May 5 (Reuters) - Boeing Co and its supporters on Monday vowed to fight for $2.1 billion in funding for 22 EA-18G electronic attack planes in fiscal 2015 to keep the plane's St. Louis production line running past 2016 and preserve 60,000 jobs around the country.
Hundreds of Boeing workers attended a rally at the plant on Monday to mark the delivery of the 100th EA-18G "Growler" to the Navy, as the company highlighted the plane's unique capabilities and accelerated its campaign to keep the program alive.
Lawmakers from Missouri said they had already gathered over 80 signatures from Republicans and Democrats in the House of Representatives, and the International Association of Machinists said it would send 26 members to Washington next week to lobby for continued production of the planes.
Senator Claire McCaskill, a Missouri Democrat and member of the Senate Armed Services Committee, said the on-time, on-budget performance of the Boeing program marked a stark contrast to Lockheed Martin Corp's F-35 fighter program, whose cost overruns and delays she described as "embarrassingly bad."
Boeing officials say the Growler, which provides electronic jamming and surveillance, will work together with F-35s on the deck of Navy carriers, but executives say the Growler could also take over some missions now done by strike aircraft.
McCaskill said the F/A-18 Super Hornet offered 85 percent of the F-35's capabilities at far less cost. She said the Navy needed both planes, but added, "at some point you cut your losses."
F-35 backers worry that the Navy could back out of its plans to buy 260 of the Lockheed jets and start using them from 2019 on, if Congress keeps funding more of the Boeing aircraft.
As it battles for more funding, Boeing has downplayed the importance of the F-35's "stealthy" characteristics, arguing that enemy radars have advanced and the Growler is the only U.S. warplane that can deal with a full range of enemy radar threats.
Lockheed insists that the F-35 was designed to go into battle without support aircraft like the EA-18G, and offers advanced stealth and electronic warfare capabilities of its own.
Boeing is also vying for future orders of 24 to 60 F/A-18 Super Hornets in the Middle East, said Mike Gibbons, program manager for the F/A-18 and EA-18G jets, which are based on a common airframe.
Gibbons told reporters Boeing hoped to hear back from the unnamed Middle Eastern buyers by the end of the year, and Canada is due to unveil its fighter plans in coming months.
Boeing this week showed Denmark its F/A-18 simulators, and will do a flight demonstration next week, Boeing officials said.
The company got bad news on Monday when the House Armed Services Committee proposed adding $450 mln to the U.S. Navy's fiscal 2015 budget for just five more Boeing Co EA-18G electronic attack planes, well short of the 22 jets on the Navy's list of "unfunded priorities."
In a statement, the committee said it found savings across the Defense Department to fund many key programs, but "there simply was not enough to save every program."
The panel said Buck McKeon "recognizes the need for continued production of the EA-18G Growler but was only able to fund five additional aircraft."
Brett Lambert, who headed the Pentagon's industrial policy office until last August, said the committee's move underscored the challenging budget environment and competing priorities. "It's a recognition of the reality on the ground. There are a lot of deserving programs, there's just not enough money."
Gibbons said Boeing had reached an agreement with the Navy on the terms of a multibillion-dollar contract for 47 more F/A-18 fighter jets and EA-18G electronic attack planes that were funded in fiscal years 2013 and 2014. He said he expected the contract to be signed in the next two months.
Gibbons said the deal would include 11 F/A-18 Super Hornets funded in fiscal 2013, 21 EA-18G "Growlers" funded in fiscal 2014, 12 Growlers for Australia and three EA-18G planes included in a legal settlement with the U.S. government.
(Reporting by Andrea Shalal; Editing by Bernard Orr)