I know of one who did Masters at the USAF Institute of Technology. He was on the pioneering team on the JF-17 in 1997 with the Chinese team. He left right after it, joined NASA and is currently the head of an aerospace engineering department at a university in the United States.
PAF does send engineers abroad for further academics....but there is no different if you get qualified...the idea is to get educated. You get educated, you can do wonders (and preferably in a team)....you get qualified, and that is best for yourself solely (which happens frequently amongst Pakistanis....grab 1st place for a medal on the wall). From what I saw recently at PAC, that a lot of engineers knew their stuff academically but very little practical applications. And complete lack of passing on knowledge to the younger generation(s), who are basically the future to the country's air force.....