In the post-credits' scene, when Mack comments on one of the actors from A Bug's Life, he says that they are just using the same guy over and over again. Ironically, Mack is voiced by the same actor that plays the Hamm Truck in Toy Car Story, the Abominable Snowplow in Monster Trucks, Inc., and the P.T. Flea Car in A Bug's Life (this may be an intentional joke put into each movie).
The movie theatre during the day.
In Cars 2, the theater is passed by, and the marquee reads The Incredimobiles, a reference to The Incredibles.
Interestingly, the films showing at the theater in each of the first two Cars films are parodies of other films scored by each film's respective composer. Toy Story, Monsters, Inc. and A Bug's Life, as well as the first Cars movie, were all scored by Randy Newman, while The Incredibles and Cars 2 were both scored by Michael Giacchino.