A transcript Robert Gibbs's press gaggle aboard Air Force One:
MR. GIBBS: About 15 minutes ago, the President began a meeting with General McChrystal. The President called General McChrystal Wednesday prior to the three-hour meeting that happened in the Situation Room that General McChrystal, among others, joined by video teleconference. During the telephone call, the President learned from General McChrystal that he would be in London while the President was in Copenhagen, a short flight away. The President wanted to take the opportunity to get together with General McChrystal and continue the conversation that they had as part of the meeting on Wednesday.
According to reports, the meeting lasted about 25 minutes.