Originally posted by Orion's Star

I would guess that the Navy knows. The Army knows (see: Lost city [sg-1]), the marines know, and I would guess that the Navy does to. It wouldn't make sense to NOT have them know, since all the joint chiefs consult with the president and advise him on military matters. They also have a lot of aircraft and technology that would most likely be used at some point for the stargate program.
As for Sheppard, it has never been directly stated (unless someone can prove me wrong on this one) that he is Air Force, but I think we're just supposed to assume that he is. In Rising he wore a USAF pilot's jacket, and if someone could get a screencap of his nametag, I think it said USAF after his name (also see Intruder). And he does fly the X-302, which is technically a USAF craft that has USAF pilots flying it. The Air Force also flies helicopters, though the list of choppers John has supposedly flown comes from multiple branches and is kind of hard to believe.
We never saw what type of chopper he was flying in Phantoms, although he did say he was doing search and rescue. The USAF's main helicopter is the HH-60G pavehawk, which specializes in search and rescue, although we can't be sure yet. Does anyone know kind of helicopter he was flying in Rising?
Edit: Nope, Sheppard IS Air Force. Look at his name patch in this pic (warning: LARGE pic!)
http://www.stargatecaps.com/sga/s1/1...l/101x313.html
On his tag is also an AF Command Pilot Wing, which you can compare to this picture located here.
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