United States Air Traffic on September 11, 2001

In September 2019, approaching the eighteenth anniversary of September 11th 2011, a Reddit user shared the following GIF purportedly depicting United States air traffic during and after the attacks to r/DamnThatsInteresting:

In its GIF format, the image animated for several seconds; a small timestamp in the lower left hand corner commenced at 7:12 AM on September 11 2001 and ended five hours later at 12:12 PM.

Noted in a previous fact check was that the attacks are widely considered to have “started” at 8:46 AM EST, when American Airlines Flight 11 struck the North Tower of the World Trade Center (WTC 2). The GIF’s earlier portion depicts a number of aircraft indicated in yellow across the Eastern Seaboard (versus the West Coast where the first plane struck at 5:46 AM). By 9:30 AM on the timestamp, air traffic had markedly decreased across the US.

At the 10:00 AM EST (7:00 AM PST) timestamp, a small fraction of the same number of aircraft remained in the sky. And one hour after that, a far smaller fraction still of presumably essential aircraft remained aloft fewer than three hours after the first plane struck.

In addition to the graphic, the post’s first updated comment claimed that the visible halt of all air traffic in the United States was further notable:

It turns out that the person who had to make the EXTREMELY DIFFICULT decision to ground air traffic across the entire country on 9/11… was on his first day on the job.

EDIT: He was was still an experienced guy (as you’d expect). He’d worked at the FAA for over 25 years, but nothing can really prepare you for such an unprecedented decision.

The comment’s second portion required no additional verification, as it is well understood that many aspects of 9/11 were unprecedented. In September 2011, Jalopnik reported:

As terrorists seized control of four airplanes on Sept. 11th, 2001, Ben Sliney, chief of air-traffic-control operations at the FAA’s command center in Herndon, Va., gave the unprecedented order to ground 4,000-plus planes across the nation and redirect any in the sky to the nearest airport. It was his first day on the job.


But due to Ben Sliney, the Federal Aviation Administration’s National Operations Manager on duty that fateful morning, possible harm, at least by the thinking at the time, was averted. Sliney made the gutsy — and completely unprecedented — call to ground every single commercial airplane in the country.

Some initial information about the broader events in air traffic that day was published by TIME magazine on September 14 2001. The unprecedented action ordered by Sliney on what was indeed his first day as the FAA’s National Operations Manager is known as a “national ground stop,” placed into effect under the Plan for the Security Control of Air Traffic and Air Navigation Aids (SCATANA) at 9:25 AM EST, 12 minutes before American Airlines Flight 77 struck the Pentagon at 9:37 AM EST:

With conflicting reports coming in, and controllers attempting to track ‘invisible’ airplanes, the news of the planes hitting the World Trade Center rocked the FAA headquarters. FAA Administrator Garvey, most likely in full consultation with Secretary of Transportation Norm Mineta, decided to implement a ‘ground stop’ on New York City airports. Although the FAA doesn’t technically close an individual airport, a ground stop prevents any plane, commercial or private, from taking off from that airport and can require incoming flights diverted. When reports that a plane or planes might be headed towards Washington, the FAA HQ on Independence Avenue was evacuated.

At 9:25, Garvey, in an historic and admirable step, and almost certainly after getting an okay from the White House, initiated a national ground stop, which forbids takeoffs and requires planes in the air to get down as soon as reasonable. The order, which has never been implemented since flying was invented in 1903, applied to virtually every single kind of machine that can takeoff — civilian, military, or law enforcement. The Herndon command center coordinated the phone call to all major FAA sites, the airline reps in the room contacted all airlines, and so-called NOTAMS — notices to airmen — were also sent out. The FAA had stopped the world.

Flight 77 was the third of four planes that would crash on American soil that morning. At 10:03 AM, United Flight 93 out of Newark, New Jersey crashed into a field in Shanksville, Pennsylvania, killing all 44 people aboard — passengers, crew, and hijackers. The field in Shanksville was not the target sought by the hijackers, but passengers aboard the planes were made aware of the ongoing attacks and fought back. The White House or the Capitol Building were considered likely planned targets for the fourth and final hijacked plane.

An annotated video just under two minutes long of the same sped up footage in the GIF was shared to YouTube in August 2011, with a shorter version shared by the same channel.

In September 2009, Smithsonian National Air and Space Museum published the 22-second-long time-lapse version to their channel, with linked timestamps in its description. The time for the issuance of the national ground stop on that morning is provided as 9:45 AM EST, versus 9:25 AM in the 2001 TIME article:

This animation was created by NASA using FAA air traffic control data from September 11, 2001. It shows the rapid grounding of air traffic across the US, and redirection of incoming international traffic, in response to the 9/11 terrorist attacks. Time is at lower left, number of planes in the air lower right. At 9:06am, FAA issued a ground stop to all traffic not yet departed that would encounter NY airspace [“tier one”- NY, DC, Boston, Cleveland] . A series of rapid decisions followed, including redirecting inbound traffic away from NY and warning airplanes in the air of potential cockpit intrusion. At 9:45am, FAA Command Center decided to close all US airspace for the first time in history. Within a few hours, all commercial air traffic was grounded. This animation is displayed in the National Air and Space Museum’s “America by Air” exhibition.

Both the “U.S. Air Traffic on September 11, 2001” GIF and video iterations dating back to 2009 at the latest are accurate. They are NASA and FAA-created animations of the drawdown of all non-essential air traffic over the United States on the morning of that day.