The Air Force on Monday revealed its long-range plan to eventually jettison its supersonic B-1 and stealthy B-2 bombers earlier than planned while keeping the venerable B-52, an aging Cold War workhorse that first flew in 1954 and was last built in 1962, flying into the 2050s.

The Air Force confirmed that it plans to send its two newer bombers into early retirement, but keep the B-52 in the inventory well past its 100th birthday.

“With an adequate sustainment and modernization focus, including new engines, the B-52 has a projected service life through 2050, remaining a key part of the bomber enterprise well into the future,” said Gen. Robin Rand, Air Force Global Strike Command commander, in a statement issued by the Air Force.

But today’s B-52 has evolved from the planes first flown in the '50s. The Stratofortress has undergone numerous upgrades and modernization over the years, including the addition of an advanced communications system that displays real-time intelligence feeds overlaid on moving maps.

The B-1 conventional bomber and the B-2 stealth bomber are also getting upgrades in the Air Force budget, but eventually their mission will be taken over by the new B-21 long-range stealth bomber, now in the design stage. B-1s were supposed to fly into the 2040s and B-2s until 2058, but the new plan moves their retirement up to the early 2030s, Air Force Magazine reported.

While the B-52 will continue as a conventional bomber, it will also carry the new long-range stand-off nuclear cruise missile.

The Air Force budget request for fiscal 2019 includes money to replace the B-52’s “inefficient and aging engines,” according to the Pentagon budget overview.

“The Air Force will update the B-52 bomber fleet and fund development of replacement engines,” said Air Force Secretary Heather Wilson. “We will also continue necessary B-1 and B-2 modifications to keep them relevant until the B-21s come on line.”

The Air Force plan calls for the B-1s and B-2s to be “incrementally retired,” once enough B-21s are operational. “If the force structure we have proposed is supported by the Congress, bases that have bombers now will have bombers in the future,” Wilson said. “They will be B-52s and B-21s.”

The Air Force has 76 B-52s based primarily in Barksdale Air Force Base, La.; Minot Air Force Base, N.D., and Andersen Air Force Base, Guam.

In all, 744 B-52s were produced by Seattle, Wash., and Wichita, Kan., plants between 1952 and 1962, according to Boeing, the maker of the iconic plane.