The United States Air Force plans to keep its aging KC‑135 Stratotanker fleet in service through the 2040s, using the aircraft to refuel the forthcoming B‑21 Raider stealth bomber. About 370 KC‑135s remain active, with the oldest units approaching 70 years old.
Although the newer KC‑46 Pegasus is gradually replacing the KC‑135, technical issues, budget constraints, and the need to maintain a large tanker inventory have slowed the retirement process. The Air Force intends to purchase at least 259 KC‑46s, with a possible increase to 319. Under the current schedule, the B‑21, expected to enter service in 2027, will rely on a mix of KC‑135 and KC‑46 tankers for in‑flight refueling until the 2040s.