How September 11, 2001 changed aviation security and air travel

If you go through security today, unpack your laptop, put your liquids bag on the belt and then take a seat behind a locked cockpit door, you are experiencing the consequences of a single morning. On September 11, 2001, terrorists hijacked four airliners in the US and used them as weapons. This look back explains what happened in air traffic that day, which rules came out of it, which airlines did not survive the crisis – and why spotting at the airport fence has changed since then.

The short answer

September 11, 2001 fundamentally changed civil aviation because it made a scenario real that the security system was not designed for: the aircraft itself as a weapon. The immediate consequences were airspace closed for days in North America and a deep drop in demand. In the long run, they led to reinforced cockpit doors, government-run passenger and baggage screening, new agencies such as the US TSA, common EU aviation security law and, in Germany, the Aviation Security Act (Luftsicherheitsgesetz). Many of the detailed rules you encounter at security today only came later, after further attempted attacks.

The morning of September 11

All four flights were scheduled domestic services to the West Coast – with full tanks for a transcontinental flight. That made them attractive to the attackers.

Flight	Aircraft	Route	Target of the attack
American Airlines 11	Boeing 767-200ER	Boston Logan → Los Angeles	North Tower of the World Trade Center, 8:46 a.m. local time
United Airlines 175	Boeing 767-200	Boston Logan → Los Angeles	South Tower of the World Trade Center, 9:03 a.m.
American Airlines 77	Boeing 757-200	Washington Dulles → Los Angeles	Pentagon, 9:37 a.m.
United Airlines 93	Boeing 757-200	Newark → San Francisco	Crashed near Shanksville, Pennsylvania, 10:03 a.m.

The types involved are still familiar to spotters today: the Boeing 767-200 and the Boeing 757-200, both the backbone of US domestic fleets at the time. How to tell the two types apart is covered in the guide How to tell a Boeing 757 from a 767. The airlines involved were American Airlines and United Airlines, and the departure airports were Washington Dulles, Newark and Boston Logan.

On Flight 93, passengers and crew learned through phone calls what had happened to the other aircraft and fought back against the hijackers. The aircraft never reached its target. That moment permanently changed behavior on board: the old rule of thumb to stay calm during a hijacking and wait for negotiations no longer applied afterward.

A continent on the ground

That same morning, the US Federal Aviation Administration (FAA) ordered a nationwide ground stop. Every civil aircraft in the air had to land at the nearest suitable airport, and takeoffs were banned. Only military, police and rescue flights were still allowed to fly. It was the first unplanned complete closure of US airspace ever, and Canada closed its airspace too.

For transatlantic traffic, this meant that hundreds of long-haul flights were already over the Atlantic and could neither turn back nor continue into the US. Canada took them in as part of Operation Yellow Ribbon. Depending on the source, between a good 220 and just under 240 aircraft carrying more than 30,000 passengers landed at Canadian airports, many of them in Halifax, Gander, St. John’s and Vancouver. In tiny Gander in Newfoundland alone, 38 diverted airliners stood on the apron – an extraordinary sight for an airport of that size. Residents housed the passengers in schools, churches and private homes for days.

From September 13, civil flights were gradually allowed to resume. First the stranded aircraft were flown to their destinations, then a limited scheduled service started up. Washington National Airport, known to spotters today for Gravelly Point Park, stayed closed until early October because of its proximity to government buildings. For US Airways, which had an important base there, this was a heavy blow.

The locked cockpit door

Before 2001, the cockpit door was a light partition. It was often not locked all the time, and on some flights passengers could even visit the cockpit. The attackers exploited exactly that openness.

That is why the FAA required reinforced, break-in-resistant and bullet-resistant cockpit doors from January 2002. By April 2003, all US airlines had retrofitted them. ICAO adopted the requirement into its international standards, so practically every scheduled airliner today has such a door. It stays locked during the flight, the crew uses a camera or peephole to check who is outside, and the crew alone decides whether to open it.

The door has its own aftermath: in the crash of Germanwings Flight 9525 in March 2015, the copilot locked the captain out. Afterward, EASA temporarily recommended that two people must always be in the cockpit; that recommendation was later turned back into a risk assessment by the airlines. For you as a photographer, all this mainly means that cockpit visits in flight no longer exist. What is allowed on the ground is explained in the article Photos in the cockpit.

Security becomes a government matter: TSA, EU and Germany

USA: the Transportation Security Administration

Until 2001, screening in the US was mostly carried out by private contractors on behalf of the airlines – with varying quality and high staff turnover. With the Aviation and Transportation Security Act, signed on November 19, 2001, the federal government took over responsibility. The newly founded TSA hired its own screening staff, and from December 2002 every checked bag was screened for explosives. At the same time, the Federal Air Marshal Service was massively expanded, and from April 2003 the first armed pilots flew under the Federal Flight Deck Officer program.

EU: common rules for the first time

In Europe, aviation security had until then been largely left to the individual states. With Regulation (EC) No. 2320/2002, the EU created uniform basic standards for screening, access to security areas and background checks of personnel for the first time. In 2008 it was replaced by Regulation 300/2008, which still forms the framework today. What it says and what it means for spotters is explained in the article on the EU aviation security regulation. The distinction between public and restricted areas is covered in the guide to landside, airside and the security area.

Germany: the Aviation Security Act

Germany consolidated the rules in the Luftsicherheitsgesetz (Aviation Security Act), which came into force on January 15, 2005. One trigger for the debate was an incident in January 2003 when a man circled above the skyscrapers of downtown Frankfurt in a stolen motor glider. The most debated provision was Section 14(3), which was meant to allow the shooting down of a hijacked passenger aircraft as a last resort. The Federal Constitutional Court declared this rule unconstitutional on February 15, 2006: the state may not sacrifice innocent people on board to save others. The rest of the law still regulates background checks, screening and security areas – including the training of screening staff, as the article Becoming an aviation security assistant shows. You can find the details in the article on the Aviation Security Act.

Screening gets stricter layer by layer

Many rules you encounter at security today do not come directly from autumn 2001. They were added after later attempted attacks, but were built into the system that emerged after September 11.

When	Trigger	New measure
Autumn 2001	September 11 attacks	Knives and other blades banned from carry-on luggage, stricter screening, more staff
December 2001	attempted attack with explosives in a shoe on a transatlantic flight	Shoes come into focus; in the US, generally removed from August 2006
December 2002	US legal requirement	Explosives screening for all checked bags in the US
August 2006	foiled plot involving liquid explosives in the UK	Quantity limit for liquids, in the EU from November 2006
December 2009	attempted attack on a flight to Detroit	Expansion of body scanners, trials in Germany from 2010 as well
from the 2010s	Data-based advance screening	Passenger data is checked against watch lists before the flight

In recent years, the rules for liquids have been relaxed and adjusted several times with new CT scanners. What applies depends on the departure airport and the equipment used – check your airport’s information before every trip. How to get expensive camera gear through security with as little stress as possible is covered in the guide Camera gear in carry-on luggage. And why you are better off not taking photos at the checkpoint itself is explained in the article Taking photos at security checkpoints.

An industry in free fall

The attacks hit aviation during an already weak phase: the economy was cooling and many airlines were heavily in debt. After airspace reopened, passengers stayed away, US airlines cut their capacity by almost a fifth, and aircraft were parked in large numbers. On September 22, 2001, the US passed an airline relief law that provided up to 10 billion dollars in loan guarantees in addition to direct payments.

For several well-known names, any help came too late:

• Swissair: The Swiss national airline was already weakened by its expensive investment strategy. On October 2, 2001, the fleet stayed on the ground because there was no money left for fuel. The grounding is considered one of the most dramatic moments in European aviation history.
• Sabena: The Belgian airline was on the same drip through its Swissair stake and went bankrupt in November 2001.
• US Airways: Weakened by the long closure of Washington National, it filed for Chapter 11 bankruptcy in August 2002.
• United Airlines: In December 2002, United, one of the directly affected airlines, followed into Chapter 11 proceedings.

The Concorde (type profile) was also caught in this undertow. It returned to scheduled service in November 2001 after the Paris accident, of all times when the premium segment across the Atlantic collapsed. In 2003 it was over. The causes of these bankruptcies and farewells went back further than September 11, but the attacks acted as an accelerant.

What changed for spotters

Until 2001, plane spotting at many airports was a tolerated, often welcome hobby. After the attacks, the view of people with telephoto lenses at the fence changed. Security staff and police approached spotters more often, and some visitor areas were temporarily closed or more heavily monitored.

Just a few weeks later, the Kalamata case made things worse: in November 2001, fourteen spotters in Greece were arrested on suspicion of espionage after an open day at a military airfield and were acquitted only on appeal. How those years shaped the scene is described in the article on the history of plane spotting.

In the long run, though, a different approach prevailed. Instead of driving spotters away, many airports rely on cooperation: anyone who regularly stands at the fence knows normal operations and notices anything unusual. Programs such as Airport Watch turn spotters into security partners. In addition, there are observation decks and spotter hills that are deliberately offered as official places to take photos – from Frankfurt Airport (see Plane spotting in Frankfurt) to the big US airports.

Places of remembrance for aviation fans

If you travel in the US, you will pass several places connected to September 11. In Washington, the Pentagon lies only a few kilometers from Reagan National Airport and is easy to see from the window on approach over the Potomac. At Gravelly Point Park you experience these approaches up close. The Steven F. Udvar-Hazy Center, right at Dulles Airport where Flight 77 departed, is a must-visit for aviation fans anyway thanks to its exhibition, as is the National Air and Space Museum downtown. In Boston, you look out over Logan Airport from Castle Island, where two of the flights took off. And in New York, a visit to the memorial at the World Trade Center combines well with plane spotting at JFK.

Conclusion

September 11, 2001 marks the transition from a comparatively open to a tightly secured aviation system. The locked cockpit door, government-run security screening and common European law go directly back to that day. Many everyday rules such as the liquids restriction came later but follow the same logic. For the industry, it was one of the most severe crises in its history; for spotters, the start of a period in which trust at the fence had to be rebuilt first.