The Pentagon had a security crew with access to FIM-92A Stinger MANPAD shoulder fire missiles. Mysteriously, they seemed to be on a coffee break at the time the 757 slammed into the building.
Meanwhile, F-15 and F-16s scrambled to intercept the planes were ordered to not break the sound barrier, guaranteeing they would never catch up with the hijacked 757 and 767s.
The top speed of the F-16 is 1320mph
The top speed of the F-15 is 1600mph
The cruise speed of a jet airliner is 530mph.