If I remember correctly the defense arm of Boeing only accounts for about 33% of their total sales. And European sales are less than 10%.
So if that dried up Boeing would take a hit, but it would never bankrupt them
Boeing is not going bankrupt but they will continue their decline.
Their rocket fizzled and leaked, they still have lots of liability for existing B737 Max' and so many other problems and failures they are dealing with now. The travelling public does NOT trust Boeing. If it's Boeing, I'm
not going feeleing has not showed any signs of slowing down.
And mostly, there is no doubt that Trump turning their friends and allies into enemies who have "been ripping off America for years'.. etc will sour people on Boeing, the quintessential American icon. Plus their airliners are slipping behind Airbus' because they simply make better, more efficient, technically advanced, fuel efficient and comfortable airlines than Boeing.
And I have heard that there are lost of non-US parts sub-contractors who are being approached by Airbus to help Airbus deliver more aircraft. Trump doesn't realize that fresh entrepreneurs are just going to jump in, start a capital intensive business on teh HOPE that Boeing may select them. That industry is all about connections to get the biz.
Militarily... what country in their right mind is going to trust the arms the US sells them with more paperwork in the agreement than in the Pilots Operating Manuals and Maintenance Manuals? If the US can't sell their military and commercial products ABROAD (NOT just Europe no longer trusts Trump) then the number their development costs are amortized over, will skyrocket per unit for internal consumption.
The Europeans have woken up and are going to take this wake-up call as an opportunity to develop their own technologies and manufacturing to truly have their own military hardware in their own control. Not be betrothen to this or a future fascist demagogue who has proved his will SWITCH OFF Us equipment because of an ill-advised,
staged, temper tantrum in a White House meeting because Trump has animosity towards an ally ... until the day Trump was elected. And you betcha that they will poach US client states.