We always do...
In the Med?
Honestly, I don't know. I would assume -- underlining assume -- that there's one within a couple days' sailing in case it's needed for medevac or logistical support for the ongoing effort in Iraq. We certainly have enough long-range bombers within range to keep the bad guys' heads down until the cavalry arrives (and yes, I know referring to a carrier group as "the cavalry" is abusing the analogy, but you know what I mean).
The USAF could drop a lot of ordnance anywhere in the region in a matter of minutes from Qatar and Dubai, and could get a lot of tonnage to Baghdad International in a matter of hours. I can't think of a better regional hub.
More so than the Army and Marines, the flyboys are well-rested and have had time to plan for contingencies and train for any likely scenario. Air supremacy in the region is not seriously challenged, even considering the USAF alone; team up the USAF and IAF, and if a gnat farts, an AWACS will hear it, target it, and vaporize the bug before the stink fades.
The Air Force and Naval Air Wings have a combination of combat experience and relatively (that is, relative to the ground forces) fresh horses. If anyone decides to create a definable battle line or an identifiable headquarters, he will find unholy hell raining down on his head. Without a damned thing he can do about it.