how long was airspace closed after 9/11

U.S. airspace was effectively shut down for about two days after 9/11, with limited flights beginning to move again on September 13, 2001.

Quick Scoop: What Actually Closed, and For How Long?

• At 9:45 a.m. Eastern on September 11, 2001, the FAA ordered a complete shutdown of U.S. airspace to civilian traffic, an unprecedented move in aviation history.

• By about 12:16 p.m., all commercial and private flights had been brought down, clearing U.S. skies in roughly three and a half hours.

• Civilian air traffic began to resume gradually on September 13, 2001, meaning airspace was broadly closed to normal commercial travel for around 48 hours.

• The restart was phased: first stranded planes were allowed to complete their trips, then limited scheduled services returned under much stricter security rules.

• It took several more days to clear the passenger backlog and for flight schedules to look anything like “normal” again.

Key Timeline (Mini-Section)

• Morning of Sept 11, 2001: First plane hits the World Trade Center; the FAA starts issuing ground stops, then orders all aircraft to land as soon as practical.

• 9:45 a.m.: Full closure of North American airspace (U.S. and Canada) is ordered.

• 12:16 p.m.: U.S. airspace is effectively clear of commercial/private flights.

• Sept 13, 2001: Civilian air traffic is officially allowed to resume on a limited basis, under tighter security.

Short Story-Style Snapshot

Imagine looking up at the sky on a normal Tuesday morning and seeing the usual thin white lines of jets crossing paths overhead. After the attacks, controllers received orders to get every plane on the ground as quickly and safely as possible, with more than 4,500 aircraft in the air that had to divert, dump fuel, and land at unfamiliar airports. Within a few hours the sky over the U.S. went eerily quiet, and for roughly two days, commercial air travel simply stopped while authorities figured out what was safe, what had to change, and how to reopen without repeating the same vulnerability.

Simple HTML Table of Timeline

html

<table>
  <thead>
    <tr>
      <th>Date / Time</th>
      <th>What Happened</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>Sept 11, ~9:45 a.m. ET</td>
      <td>FAA orders complete shutdown of U.S. airspace to civilian flights.[web:3][web:5]</td>
    </tr>
    <tr>
      <td>Sept 11, 12:16 p.m. ET</td>
      <td>All commercial and private aircraft are on the ground; skies effectively cleared.[web:3][web:1]</td>
    </tr>
    <tr>
      <td>Sept 13, 2001</td>
      <td>Gradual resumption of civilian air traffic under new security rules.[web:7][web:6]</td>
    </tr>
    <tr>
      <td>Following days</td>
      <td>Backlog of passengers cleared; flight schedules slowly normalize.[web:7][web:6]</td>
    </tr>
  </tbody>
</table>

In forum discussions, you’ll often see people say “flights were grounded for two days,” which is a good shorthand: skies cleared within hours, but practical commercial travel was mostly halted from late morning September 11 until September 13.

TL;DR: Airspace was shut to normal commercial flights for about two days after 9/11, with the order going out late morning on September 11 and limited flights resuming September 13, then ramping up over several more days.

Information gathered from public forums or data available on the internet and portrayed here.