Interstate commerce clause aside (although it certainly has some relevance here), there are also international treaties governing this stuff. This gives the Feds some authority in this domain. Airspace is kind of equivalent to "navigable waters".
I'm not sure what would happen if some state decided to regulate its federally uncontrolled airspace, though.
Guns, however, were available, and it matters not what kind of gun we are talking about, but how it compares to the military standard of the day. In 1776 a musket was the standard. In 2003, the full auto, night vision and lazer range finder equipped, assault rifle with hi-cap mags is the kaboomer du jour. Unless we as citizens can maintain a personal arsenal equivilent to the military, the 2nd amendment is being violated.
And yes, that means that I belive we can own grenades, LAWs, SAMs, tanks, and even fighter aircraft and helicopter gunships.
And for the paranoid that will think that if we had this, the nation would be rubble within weeks, these things are all available on the black market, and would already have been put to use here in a crimminal way, if that was the nature of the American that could afford such toys.