So we have to buy what they are buying (or selling)
I'm struggling on that comment - as this thread is about the F35, apart from the Phantom, which US fast jets have we bought since the Suez conflict? I would suggest we have partnered with Europe far more ....
Granted on the RW/heavy side we have invested in US products (Chinook / C17 / C130 / Sentinel / Sentry / Tri*) but even then this is balanced by the Puma / Wessex / VC10 / BAe146 / Nimrod / Belfast etc.