There are some truly hilarious scenes in PLANES, TRAINS, AND AUTOMOBILES, but they aren't very appropriate for children -- at least younger ones. In one scene, the two men are forced to share a bed in a sleazy motel and Nell unconsciously cuddles with Neal in his sleep. When they wake up, horrified, Neal asks Nell where one of his hands is. He replies, "Between two pillows." Neal exclaims, "Those aren't pillows!"
Neal's love-hate relationship with Nell does not always serve as an appropriate role model, as he repeatedly tells off Nell and berates his oddball behavior. Yet, even Neal realizes his bad behavior and regrets it on several occasions, and by the end of the film, the two realize that together they've accomplished more than they could separately. Overall, teens would get a chuckle from the film's many escapades, and their parents would probably enjoy viewing it with them -- with the understanding that the humor is far from clean.