Blast From The Past

Mail recovered from the 1955 crash of United Airlines Flight 429

United Airlines Flight 629 was blown up with a dynamite bomb placed in the checked luggage on November 1, 1955. The explosion occurred over Longmont, Colorado. All 39 passengers and five crew members on board were killed in the explosion and crash.
Investigators determined that Jack Gilbert Graham was responsible for bombing the airplane to kill his mother as revenge for his childhood and to obtain a large life insurance payout. Within 15 months of the explosion, Graham—who already had an extensive criminal record—was tried, convicted, and executed for the crime. - paraphrased from Wikipedia

Not quite a year later United Airlines Flight 409 crashed into Medicine Bow Peak in Wyoming, about 100 miles farther north.

The letter was addressed to Posthip Scott's dad and was eventually delivered. Via Posthip Scott.