Maybe McCain is confused, but this is like his attack on the new GI Bill. factcheck.org tells us the truth:
A McCain TV spot falsely insinuates that Obama canceled his visit because "the Pentagon wouldn't allow him to bring cameras."
McCain's facts are literally true, but his insinuation – that the visit was canceled because of the press ban or the desire for gym time – is false. In fact, Obama visited wounded troops earlier – without cameras or press – both in the U.S. and Iraq. And his gym workouts are a daily routine.
The Obama campaign canceled the visit with wounded troops at Landstuhl Regional Medical Center in Germany, Obama says, when he learned that the Pentagon would not allow him to bring along a retired Air Force major general who is serving as a foreign policy adviser to the campaign. Obama says that "triggered then a concern that maybe our visit was going to be perceived as political."
disclaimer: I'm on the advisory board of factcheckED.org, the educational arm of factcheck