The standdown claim is starting to lose credibility.
To reach their peak speed, the fighters would've had to use their full afterburner, which only lasts a few minutes. A full load of fuel and missiles is likely to slow down fighters. At 577mph, the fighters were traveling well above normal cruising speeds. [http://911myths.com/html/f-16_speeds.html]
] - the pros and cons, take everything with a grain of salt
] - discusses F-16 speeds, Payne Stewart interception, the 67 pre-9/11 interceptions, hijacked jets' transponders and radar, war games, Andrews AFB v. Langley AFB