You know how this goes: in 2001, Richard Reid - AKA "The Shoenabomber" - tried to blow up a plane with explosives he'd hidden in his shoes. It didn't work, because it's a stupid idea - and then we all took off our shoes for a quarter-century:
https://en.wikipedia.org/wiki/Richard_Reid
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In 2006, a gang of amateur chemists hatched a plan to synthesize explosives in an airplane toilet sink, scheming to smuggle in different reagents and precursors in their carry-on luggage, then making a bomb in the sky and taking down the plane and all its passengers. The "Hair Gel Bombers" were caught before the could try their scheme, but even if they had made it onto the plane, they would have failed.
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