As threats to flight security evolved, so did the screening process. Over time, passengers had to remove an increasing number of items and place them on bins for scanning.
BELTS, COATS & SHOES
footwear had to go in the bin, too.
Then after Richard Reid, also known as the "Shoe Bomber", tried to detonate a shoe bomb on a flight from Paris to Miami on Dec 22, 2001,
The US aviation authority soon banned passengers from bringing any type of knife onboard.
Some airlines also swopped out their metal cutlery for plastic ones.
Box cutters and small knifes were reportedly among the weapons used by the 9/11 hijackers.
BOX CUTTERS & METAL CUTLERY
Eventually this ban was relaxed to allow small bottles that had to be placed in plastic bags.
After British officials uncovered a plot to use liquid explosives to blow up a plane in 2006, liquids were banned altogether.
Electronics onboard were a concern since an explosive device was hidden in a cassette player in 1989 Lockerbie bombing.
Since 9/11, it has become the norm for laptops to be removed and placed in their own bins to be scanned.
The attacks showed how easily people could smuggle weapons onboard
so full-body scanners started to appear at airports by 2007.
There were initial privacy concerns with some critics calling them virtual strip searches.
The US authority also requires the doors to be able to withstand a grenade blast.
cockpit doors are now locked throughout - except for when one of the pilots goes to the toilet.
Where it was once common for children to be brought to meet pilots in the cockpit during long flights,
READ ST'S SPECIAL REPORT ON THE 20TH ANNIVERSARY OF 9/11
PRODUCED BY: tan jia ning