Qatar.
Since 1996 the US has been building in Qatar. In March 2002 the base there became
official. Buildup
continued over the summer. You might remember it was discovered that a random (?) Saudi fired a shoulder-held missile at an outgoing US plane at about that time frame.
At this point the military operations don't even need the rights to fly over Saudi Arabia. The only thing they may need is the ability to ditch there if a plane is in trouble. They probably won't even ask for it.
The Saudis are certainly not allies, and things are getting worse not better. In fact some Saudis independently
intend to cross the border into Iraq to help fight.
(Den Beste
explains how things will go for them if they do:
Someone ought to brief these young idiots on what happened to all the Pakistani jihadis who crossed into Afghanistan to fight Americans, and who died without ever even seeing an American face, killed by American bombs dropped by faceless American pilots five miles overhead, or by Hellfire missiles from Predators because an American 500 miles away pushed a button. And then they might want to consider just how easily they can be detected and bombed, once they've driven their air-conditioned 4WD Mercedes across the border into Iraq. JSTARS can pick them out of such an open expanse in an instant.)
The next question is whether Saudi Arabia is the "next" Iraq. How will they behave with a regime-changed Iraq and US forces controlling their northern border? What will the new middle east look like after a change in the balance of power? (I dunno.)