The Times of London notes this in their airline bombing plot coverage:

"Michael Chertoff, the US Homeland Security Secretary, said that the British plot was “getting really quite close to the execution stage”. For British and American crisis planners, the date August 22 looms large. This year it corresponds in the Islamic calendar to the day in 1427 which Muslims commemorate as when Muhammad took flight on the winged horse Buraq to the “furthest mosque”, usually assumed to be Jerusalem. Bernard Lewis, an expert on the Middle East, writes: “This might well be deemed an appropriate date for the apocalyptic ending of Israel and if necessary of the world.”

President Ahmadinejad of Iran has cited August 22 as the date on which he will give his final answer on nuclear development. The suggestion that the foiled British plot involved blowing up aircraft over towns and cities corresponds with a longstanding ambition held by al-Qaeda. [ Where have I heard August 22nd before? We can only pray that this is what Ahmadinejad was going for -- but I remain skeptical we've seen anything yet... -ed. ] "