Christiansen enlisted in the Army in 1944 and was trained as a paratrooper. The war had ended by the time he was deployed in 1945, but he made occasional training jumps while stationed in Japan with occupation forces in the late 1940s. After leaving the Army, he joined Northwest Orient in 1954 as a mechanic in the South Pacific, and subsequently became a flight attendant, and then a purser, based in Seattle. Christiansen was 45 years old at the time of the hijacking, but he was shorter (5 ft 8 in or 173 cm), thinner (150 pounds or 68 kg), and lighter complected than eyewitness descriptions. Christiansen smoked (as did the hijacker), and displayed a particular fondness for bourbon (the drink Cooper had requested). He was also left-handed (evidence photos of Cooper's black tie show the tie clip applied from the left side, suggesting a left-handed wearer). Schaffner told a reporter that photos of Christiansen fit her memory of the hijacker's appearance more closely than those of other suspects she had been shown, but could not conclusively identify him.