In 1997, Lockheed Martin earned the distinction of being one of two final competitors for the Pentagon’s revolutionary new Joint Strike Fighter concept program. Within four years, they had beaten out the competition at Boeing and secured victory for their X-35 concept. Five years after that, in February of 2006, the first production F-35A rolled off the assembly line and ten months later, an F-35 took to the skies for the first time. Flights of production aircraft began in 2011 and deliveries of the fighter began later in that same year.

By 2015, the Marines declared their iteration of the F-35 (F-35B) had reached initial operating capability, with the Air Force following a year later and the Navy joining the party earlier this year. All told, more than 380 of the advanced fighters have been built and shipped to bases around the world thus far… but according to the Pentagon, the most expensive aircraft ever developed in history still doesn’t appear to be ready to enter into full production.

“I’m going to make some decisions about when that full-rate production decision will be made shortly,” Under Secretary of Defense for Acquisition and Sustainment Ellen Lord said on Friday, following the revelation that a number of Pentagon officials are not planning on signing off on the F-35 entering into full-rate production until as late as January of 2021, marking yet another delay in a program that has been plagued with high profile issues and setbacks.

The Initial Operational Test and Evaluation (IOT&E) period for the F-35 was expected to finally come to a close earlier this summer, but the testing end date was pushed back due to an issue with the program’s Joint Simulation Environment.