A few of the Cars 2 easter eggs I noticed:

• “Incredimobiles” is the movie playing at the drive-in theater in Radiator Springs
• The traditional A113 can be found on the fin of one of the planes in the airport
• The tunnel that the train on the high-speed rail line went through had “1986-2011” carved over the arch signifying Pixar’s 25 year anniversary
• When they arrive in Paris, you can see a shot of Gusteau’s restaurant from Ratatouille in the foreground
• One of the banners along the track in London is advertising “Lassetires,” named for director John Lasseter
• One of the shops in London is called “Lewis,” after co-director Brad Lewis.