> Was this a real threat? Yes, there was a very serious plot to blow up planes using liquid explosives in bombs that would have worked to bring down aircraft.
Yeah. With Nitroglycerin, the stuff that explodes when you move it too fast. You could still bring this on a plane undetected in 3.4oz containers. And you can check a bag with much larger amounts.
But there was not just "a plot" to blow up a plane with liquid explosives. There was a successful attack on a South Korean plane that killed everyone on board with liquid explosives, used in 1989. Yet they don't even mention this, probably because the policy was put in place after 9/11, partly as a fear tactic to get US citizens to support the wars in Iraq and Afghanistan, partly to prevent fear from ruining the airline industry, and partly to support the new jobs program called the TSA (which was also created after 9/11).
Without fear and extensive unnecessary security measures, the TSA would not be the size it is, nor would it get the investment it gets. If you don't believe TSA is primarily a jobs program, consider that according to NPR in 2006, a government report showed that Research & Development programs were delayed when TSA funds were redirected in order to pay for personnel costs for screeners. And the TSA receives 8 billion dollars a year.
There are many ways to detect liquid explosives. By removing them from their container (or requiring specific kinds of transparent containers) and using laser scatter plotting or microwaves, or by detecting vapor emissions from an opened bottle, for example. But nobody cared about them when planes were bombed using them, and they're still not using any of these methods, 17 years after the policies were put in place. These policies are just tools used to control people.
