Royal Air Force.
"Cooperative Spirit. U.S.Air Force and Royal Air Force share training in B-2 mission, capabilities."
"A long standing exchange program under which USAF personnel trade places with those from the Royal Air Force was extended to the B-2 in 2004.
The offer to open up the secretive B-2 mission to a key ally was made by then President George W. Bush..." (1)
El poderoso B-2
Israel's ballistic missile defense system.
"Kill vehicle set to enhance Arrow-3 missile defense"
"The U.S. and Israel have started development of an upper-stage component to Israel's Arrow-3 missile defense architecture."
"The decision to add the component, which will be jointly developed by Israel Aerospace Industries (IAI) and Boeing, stems from a study conducted in 2006-07 that identified a need for it in Israel's ballistic missile defense system."(2)
From Aviation Week & Space Technilogy/February 8, 2010. (1) page43; (2) page44.