When the UK Ministry of Defence’s (MoD’s) Defence Equipment & Support (DE&S) organisation announced that: “We’ve accepted the final Tranche 1 F-35B Lightning, completing delivery of the Royal Air Force’s (RAF’s) first batch of the world’s most advanced fighter jet,” on 29 March 2026, five aircraft actually remained undelivered. Warsight reported the ‘uncomfortable facts behind UK F-35 deliveries’, which were that two aircraft were stranded on the Azores and that three more remained at Lockheed Martin’s Fort Worth factory, where they had been ‘accepted’ by the MoD but had not yet delivered.

When the three aircraft at Fort Worth were delivered on 23 April, Warsight reported this and noted that two aircraft were still on the Azores.

These final two aircraft (ZM177/BK43 and ZM179/BK45) had been stuck at Lajes since some time before 9 March 2026, although some reports suggest that an attempt was made to complete delivery on 13 March. Three F-35Bs took off with their Voyager tanker on that day, but turned back to Lajes while the tanker continued on. ZM178 then flew to Marham on 20 March, presumably after a short wait to see whether all three could fly back together sharing a tanker.

The two aircraft then remained stuck at Lajes, with periodic visits by RAF A400M transport aircraft carrying engineering personnel. Finally, the two aircraft were brought back to airworthy status and joined two aircraft (ZM143 & ZM161) returning from the United States after maintenance. All four F-35Bs finally arrived at Marham on 23 May.

Air Commodore Chris Layden, the RAF’s Combat Air Force Commander, stated, “I’m delighted to welcome the final aircraft of our initial procurement of F-35Bs to Marham. This marks an important milestone in our fifth-generation combat air power journey, reinforcing our declaration of full operational capability last year. The Lightning Wing’s stalwart service over the last year reflects how far we’ve come, with operations ranging from a truly global carrier strike deployment in 2025, to combat missions in defence of UK personnel in Cyprus and the Middle East this year. We look to the future with confidence, and this year will see us making the most of our new aircraft as we showcase our ability to project and integrate fifth-generation combat power from land and sea.”