Then-Vice President Dick Cheney recalled his actions from the Presidential Emergency Operations Center beneath the White House, during the terrorist attacks on the morning of September 11, 2001: “At about 10:15, a uniformed military aide came into the room to tell me that a plane, believed hijacked, was eighty miles out and headed for D.C. He asked me whether our combat air patrol had authority to engage the aircraft. Did our fighter pilots have authority, in other words, to shoot down an American commercial airliner believed to have been hijacked? ‘Yes,’ I said without hesitation. A moment later he was back. ‘Mr. Vice President, it’s sixty miles out. Do they have authorization to engage?’ Again, yes. There could have been no other answer. As the last hour and a half had made brutally clear, once a plane was hijacked it was a weapon in the hands of the enemy. In one of our earlier calls, the president [Bush] and I had discussed the fact that our combat air patrol–the American fighter jets now airborne to defend the country–would need rules of engagement. He had approved my recommendation that they be authorized to fire on a civilian airliner if it had been hijacked and would not divert. Thousands of Americans had already been killed, and there was no question about taking action to save thousands more.”
– Dick Cheney, In My Time, Page 3