Portland (Multnomah, Oregon)
U.S. aviation security timeline

Here are some significant events and policies in the history of U.S. aviation security: 1955 A United Airlines plane explodes after takeoff in Denver, killing all 44 aboard. Investigators blame Jack Graham for placing a bomb in his mother's luggage, apparently in hopes of cashing in on her life insurance. It is among the first major acts of criminal violence against a U.S. airliner. Graham is later convicted of murder and executed. 1960 A National Airlines plane explodes in midair, killing all 34 aboard. Investigators suspect that a passenger, bent on suicide, had brought a bomb aboard. 1961 Antulio Ramirez Ortiz hijacks a National Airlines flight to Cuba after it takes off in...