I know in the AF right now, all aircrew (pilots, WSO, loadmaters, crewchiefs) are required to fly with a weapon anytime they are not in CONUS. I thik it's about force protection, etc than about SERE.
Its because it makes the Air Force feel like they are part of the fight, personally I would not want to see some of the AF aircrew that I have flown with to be armed (some Navy guys too).
I am of the school that carrying a gun in the plane is more psychological than anything else. It probably would be more use for barter to get some Kurd or another local to help you out than to shoot someone. If I am up aginst a platoon of soldiers armed to the teeth or a bunch of angry locals (I would prefer the soldiers, they better know the value of a live prisoner), who are probably armed too since it seems like everyone in Iraq and Afghanistan seem to have an AK-47, I am not planning on being John Wayne. I don't care what kind of gun you have, 9mm, 45, M16 or a 50 cal, all the guys who think a gun is going to help you in a 'firefight' after you get shot down are living in a fantasyland.