The Navy is close to striking a deal to lump together all the fighter jets it plans to purchase over the next several years into a single large buy, in a victory for aerospace giant Boeing.

The Department of the Navy told Congress on Friday it plans to use the “multiyear authority” it was given if it could show that buying many planes together over several years would lower their costs. So the Pentagon will begin bargaining with Boeing to buy the rest of the F/A-18 Super Hornets and E/A-18G Growlers in its program of record — some 124 aircraft — which guarantees work for Boeing until 2015.

The arrangement could mean the Navy pays about $500 million less for the planes than if it had continued buying batches every year on its current schedule, which calls for ordering sets of new fighters until fiscal year 2013.

Top Defense Department acquisition officials told lawmakers about the deal in a letter Friday.

“The Department of Defense is taking essential steps toward a multi-year [contract] for 124 F/A-18 E/F and EA-18G aircraft,” two top Pentagon officials wrote in a letter Friday to the Senate. “The Navy is in receipt of a viable offer from the F/A-18 prime contractor and is actively pursing award of the [F/A-18 multiyear contract] to achieve substantial savings.”

While the contract is not signed, the letter from the Pentagon signals the decision on the deal is likely close.

The multiyear contract marks a triumph for Boeing, and potentially, a setback for the Navy’s next fighter jet, Lockheed’s F-35C Lightning II, which has faced heavy criticism for cost overruns and scheduling delays.

Missouri Rep. Todd Akin, a Republican from Missouri, where F/A-18s are built, lauded the move.

“The Navy and the DoD have made a great decision,” Akin said in an announcement. “This multiyear [contract] is the first step toward addressing the Navy’s fighter shortfall, but more needs to be done.”

The “more” could mean that Akin and other Boeing advocates will push for still more Super Hornets and Growlers beyond the multiyear deal, which might not fill a projected “fighter gap” because it includes only jets the Navy already planned to buy.

Navy officials and lawmakers on Capitol Hill have complained for years about the gap — the estimated shortfall in fighters caused by older F/A-18 Hornets wearing out faster than new F-35s can arrive to replace them. Navy and congressional studies have placed the fighter gap as high as 300, but Defense Secretary Robert Gates and others have questioned whether it or any other “gap” will really appear.

Pentagon and Navy officials had no immediate comment on the letter.

Boeing spokesman Philip Carder said the company was “pleased the Defense Department has certified this new multiyear contract, which will save the U.S. Navy and the nation 10 percent compared to single-year procurements, delivering hundreds of millions of dollars in real costs savings. We will work closely with the Navy to continue the process of finalizing a new multi year contract.”