CLEVELAND -- It caused chaos over the skies of Cleveland on Sept. 11, but we haven't heard much about one airplane until Tuesday.

Video

Hear From Controller

The surprise announcement came from an air traffic controller at the Cleveland control center in Oberlin, according to Chief Investigator Duane Pohlman.

Cleveland center controllers had already listened to hijackers on Flight 93 and steered planes out of the way.

But controllers could only watch as Flight 93 disappeared from radar. A pilot in another plane confirmed the crash.

The call came to shut down the nation's skies. NewsChannel5 showed viewers a national radar image last November. The planes -- in light green on the radar -- filled the skies on Sept. 11. Then, after the order, the planes started converging on the nation's airports.

Cleveland center had to handle most of those planes, NewsChannel5 reported.

Then, as controllers worked to clear the skies, a small plane was spotted flying erratically above the Cleveland center. The decision was made to evacuate.

"We actually evacuated, out in the parking lot," said Rick Kettell, Cleveland air traffic manager.

Luckily, controllers there had already landed most of the planes before the evacuation.

"Had that happened a half-hour earlier, I probably would have done a limited evacuation," Kettell said.

The Federal Aviation Administration is still investigating what plane that was and what it was doing.

"We never did find out exactly who it was," Kettell said. "The airplane flew off to the north, and we lost radar on it."

In the end, 4,546 planes landed safely in 2.5 hours, and there weren't even any close calls, Pohlman reported.