Slip of the tongue?

Rumsfeld admits that "Flight 93" was shot down

Was it a slip of the tongue on the part of the former Secretary of Defense?

Rumsfeld stated in a speech to US troops in Iraq (24 December 2004) that United Airlines Flight 93 was "shot down" on 9/11:

And I think all of us have a sense if we imagine the kind of world we would face if the people who bombed the mess hall in Mosul, or the people who did the bombing in Spain, or the people who attacked the United States in New York, shot down the plane over Pennsylvania and attacked the Pentagon.