On their flight to Lung Taho they are using a Bell 212 (a twin turbine version of the military Bell 202/Huey 1a). Bell did not start manufacturing the Bell 212 (known in military service as the Huey 1d) until 1967. The first models where not shipped till 1968. The movie is set in 1962.
In the scene in the bar when Beth asks for a Coke, Lawrence pulls a couple of then-current era - 1985 - Coca Cola bottles out of the cooler. The 1985 Coke bottle had a slimmer, straighter shape than the era-correct (1962), green wasp-waist Coke bottle, with a red block logo with "Coca Cola" in white script.
During the climatic scene on the bridge, Lawrence is able to distract John by pretending to hear the sound of a Russian MiG-25 fighter jet. While the movie is set in 1962, the first prototype MiG-25 did not fly until 1964 and the aircraft did not enter service until 1970.
When Bootsy Winder is in Lawrence's room on the day of graduation, she announces that she has to leave immediately because she is giving the valedictorian speech that morning at Smith College. However, Smith College is an hour and a half away from Yale.
During the Commencement Ceremony, Lawrence is listening to Game 7 of the 1962 NBA Championship. While the score is correct (Celtics 110, Lakers 107), the scene takes place in the afternoon. The game was played on a Wednesday night.
Early in the movie, after Lawrence boards the airliner and the cabin door is shut, one of the thugs chasing him tries to board the plane by jumping from the stairway. When he hits the side of the plane, the cabin door flexes and moves, revealing it to be a fake door.