There was a time when you could walk straight up to the gate without a plane ticket and cockpits had no locks. But one event changed it all.

Flying prior to September 11, 2001 looked very different.

Ask anyone old enough to remember and they will probably tell you the same thing.

While there was security screening, it wasn’t anywhere near as intrusive or comprehensive as it is today, nor were there long checkpoint lines.

Passengers were also able to arrive at the airport just minutes before a flight – and could keep their shoes and coats on as they went through a simple metal detector.

Not only that, virtually anyone could go right to the gate without a boarding pass or even showing an ID.

However, a few incidents over the years have seen changes to airport security.

In the 1970s, a series of hijackers and attempted hijacks saw the introduction of security screening for passengers and their belongings.

Then in 1988, the downing of Pan Am Flight 103 over Lockerbie, Scotland, where a bomb hidden in checked baggage detonated, was the catalyst for the screening of checked bags.

But the tragic events of the terrorist attacks in the US on September 11, 2001 is what really brought the heightened focus on aviation security that we know today.

Most people remember exactly where they were when the shocking events unfolded — when four hijacked planes crashed into the Twin Towers of New York’s World Trade Centre, the Pentagon and a field in Pennsylvania.

It was the largest terrorist attack our generation and perhaps the world had ever witnessed – and it would change the way we travelled forever.

The 19 al-Qaida-affiliated terrorists who hijacked four aircraft on the morning of September 11, 2001 exploited LAX airport’s security measures, strolling through metal detectors at four airport security checkpoints with ease and armed with deadly weapons.

By the end of the day, 3000 people were dead.

Tourism expert Dr David Beirman of Sydney’s University of Technology, said the hijacking of airlines morphed from being a threat to the aircraft and its passengers and crew, to using fully fuelled aircraft as weapons of mass destruction.

“In the six months following the 9/11 attacks there was a significant downturn in international aviation passenger numbers,” Dr Beirman told news.com.au.

“Even though the 9/11 attacks targeted New York City and Washington D.C. there was genuine fear that similar terrorist attacks could target buildings in any big city anywhere in the world.”

Dr Beirman, who released his first book in 2003, Restoring Tourism Destinations in Crisis, dedicated an entire chapter to the impact 9/11 had on the travel industry, with an emphasis on airline security.

“It was a global game-changing event for aviation and airport security,” he said.

In 2002, Dr Beirman attended two major conferences that looked into global security measures post 9/11.

“Aviation and airport security is highly regulated globally. The International Civil Aviation Organisation (ICAO) is a UN body which sets global standards for airlines and the Airports Council International sets global standards of security for airports,” Dr Beirman said.

“These two bodies along with the International Air Transport Association (IATA) convened a number of meetings and conferences to jointly decide on post 9/11 security measures which would beef up airline and airport security.”

He attended two of the conferences – one in Hong Kong and one in Vancouver – which involved a large number of airline and airport executives and security specialists.

Dr Beirman said the end result was a raft of about 200 enhanced security measures, most of them technological and “very few of which airlines and airports are prepared to disclose publicly”.

‘Pretty basic measure’

However, he said one of the most important measures and “a pretty basic one” involved strengthening and locking the doors to the cockpit.

“All four 9/11 hijackings involved the terrorists invading the cockpit, in some cases killing the pilot and taking over control of the hijacked aircraft with the dreadful outcomes we saw in New York City and Washington D.C,” Dr Beirman said.

“This has also happened in previous hijackings. Protecting the cockpit and the flight

crew is the single most effective means to minimise the likelihood of an aircraft being

under the control of terrorists.

“It is notable that since September 11, 2001 while there have been some attempts to hijack and attack civil aircraft, none have taken over the cockpit.”

Following 9/11, the Transportation Security Administration (TSA) was created and would go on to become part of the newly created of Homeland Security in the United States.

On top of this, the Aviation and Transportation Security Act required 100 per cent of all checked baggage to be screened by X-rays and the law required airlines to reinforce cockpit doors on their aircraft to prevent attackers from gaining access.

Today, travellers often stand in long lines at security checkpoints with wait times of more than an hour.

Depending on footwear, some passengers will be asked to remove their shoes, empty pockets and take laptops and other devices and accessories out, and for carry-on bags placed into a tray before stepping into high-resolution, full-body scanners.

And it wasn't just 9/11 that prompted airports to tighten security. Following a disrupted terror plot targeting an aircraft departing Sydney Airport in 2017, Australian airports were required to begin upgrading their screening equipment.

Security measures you can’t see in Aussie airports

In Australia, the Government, through the Department of Home Affairs’ Cyber and Infrastructure Security Centre (CISC), regularly reviews aviation security settings to ensure they are appropriate, and preventive security measures remain ahead of evolving threats.

“Aviation security measures, including the screening of passengers and baggage are in place to ensure the safety and security of travellers,” a Departmental spokesperson told news.com.au.

“There are many security measures in place at Australian airports, some of which are visible to the public, and some of which are not.”

“The computed tomography (CT) X-ray systems in place at Australia’s major airports to screen baggage, and the body scanners in place to screen passengers, represent the best technologies available to detect the widest range of items, including 3D printed weapons, and explosive liquids and powders, among a range of other prohibited items.”

The spokesperson said the new technologies also provide benefits to travellers, such as being able to leave laptops in bags during screening.

“Australia works closely with our international partners to promote a secure global aviation network.”

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