Many recent fighter aircraft(i.e. the JSF and the F-16) have been following a set of requirements the U.S. has given and then built competition style between a number of manufacturers. Many of these aircraft have been exported to other countries.
Does the manufacturer have the right to sell the a/c to other nation's air forces without the consent of the U.S. government?
For example: Israel recently ordered more F-16's, but did they go directly to Lockheed or the U.S. gov't first?