LONGMONT, Colo. —

On this day in 1955, United Airlines Flight 629 exploded above Longmont, Colorado.

The flight took off at 6:52 p.m. and just minutes later, two bright lights would erupt in the sky. Stapleton air traffic controllers moved quickly to identify the 30-second flashes. All flights were accounted for except for United Flight 629.

Eleven minutes after departing from Stapleton Airport in Denver on November 1, 1955, United Airlines Flight 629 exploded above Longmont, killing all forty-four people aboard. This fragment, believed to be shrapnel from the exterior of the cargo hold, was a key piece of evidence in the investigation that followed.

Shrapnel from the exterior of the cargo hold
History Colorado

The bombing of United 629 was the first case of sabotage against a commercial airliner in the US. The subsequent investigation quickly revealed John Gilbert Graham had planted dynamite in his mother’s suitcase, hoping the explosion would appear accidental so he could cash in on life insurance policies he had just bought from vending machines at the airport. The tragedy prompted stricter passenger safety policies for air travel.

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