I wonder if those from the US can explain how US manufacturers have supplied large numbers of aircraft to European forces over the years, and they have been happy to build them, but there is a huge fuss when the decision is made the other way.
Here in the UK the large aircraft component of the Air Force is made up of C-17s (US built), Tristars (US built) and multiple generations of Hercules (US built). US workers apparently felt fine building these for us. Yet if the wings of the new tanker are built in the UK and shipped to the Alabama assembly plant, there's a storm of protest.
The words "one way street", rather than "allies", spring to mind, as so often in US-UK military relations.