The requirement to remove one's shoes at airport security checkpoints can be traced to Dec. 22, 2001. That's the day admitted Al Qaeda operative Richard Reid tried and failed to ignite explosives hidden in his shoes while aboard American Airlines flight 63 from Paris to Miami.
Security protocol fluctuated at airports in the days following the attempted attack, but eventually everyone traveling through airport security checkpoints was required to remove their shoes and pass them through X-ray machines.
