Not too quickly though it seems, they were already leaving when they intercepted it?
Check it out:

Two F-16 fighter jets were scrambled Sunday afternoon to intercept a plane flying in restricted airspace over Washington, D.C., according to the North American Aerospace Defense Command.

NORAD directed the mission around 12:30 p.m. after the plane entered the Special Flight Rules Area over the capital and was deemed out of communications with air traffic controllers.

By the time the jets intercepted and visually identified the aircraft, it was leaving the restricted flight area and resumed communication with controllers, NORAD said.

“The aircraft was already on its way out of restricted airspce when our jets got up there,” said Capt. Jennifer Stadnyk of NORAD’s public affairs division.

It was not immediately clear who was piloting the aircraft or whether it had intended to stray into restricted airspace.