D. B. Cooper (alias) was a famous airplane hijacker.

At 16:35 on Thanksgiving Eve, November 24, 1971 in the United States, a man travelling under the name Dan Cooper hijacked a Northwest Orient Airlines Boeing 727-051, flight 305, flying from Portland International Airport (PDX) in Portland, Oregon, with the threat of a bomb (he had a briefcase containing wires and "red sticks").

When the plane landed at Seattle-Tacoma International Airport near Seattle, Washington at 17:45, its intended destination, he released the passengers in exchange for $200,000 and four parachutes. At 19:45 he then had the air crew take the plane back into the air, ordering them to fly towards Mexico at low speed and altitude with the landing gear down and 15 degrees of flap. At some point during the journey he jumped out of rear stairway of the airplane with the money and parachutes. The FBI believed his descent was at 20:11 over southwest Washington, because the rear stairway "bumped" at that time. His descent went unnoticed by the United States Air Force F-106 jet fighters tracking the airliner.

Despite an eighteen-day search of the projected landing zone no trace of the man was found, and it is unknown whether he survived the escape. In February 1980, $5,800 of the ransom money was found near Vancouver, Washington on the bank of the Columbia River.

The FBI questioned and then released a man by the name of Daniel B. Cooper, who was never considered a significant suspect. Due to a miscommunication with the media, however, the initials "D. B." became firmly associated with the hijacker and this is how he is now known.

The image shown is a 1981 FBI composite drawing of D. B. Cooper.

Following three similar but unsuccessful hijackings in 1972, Boeing 727 aircraft were ordered by the Federal Aviation Administration to be fitted with a device known as a "Cooper Vane", a mechanical aerodynamic wedge, which prevents the rear stairway from being lowered in flight.