The airline that Big Bird takes to Illinois is CTW - the abbreviation for Children's Television Workshop, the name at the time of the movie of Sesame Workshop, the production company behind Sesame Street.
When Bert and Ernie spot Big Bird on the ground, in one shot they switch places. Normally it's Bert who's flying the plane and Ernie in the back. But when they see Big Bird, suddenly Ernie is in the front and Bert is in the back. This is corrected a few shots later.
In the scene where the Dodos and Big Bird are arriving at Canary Road, they turn left in the street. It shows that their bird house is on the left side. However, when pulling into the driveway, they are turning right.