The car KITT from the TV series Knight Rider is featured in the TV Museum in an exhibit tilted "Things that shouldn't talk... but do". This is one of the two appearances of the car in a Simpsons episode, the other being in the episode The Wizard of Evergreen Terrace.
Other characters are Lancelot Link, Lost in Space, Salem the cat and Mr. Ed.
This episode is last appearance of American actress Isabel Sanford. She would pass away two months later. Her plea for George Jefferson to come home would be sadder in retrospect, as Sherman Helmsley (the actor who portrayed George) died in July 2012.
Additionally, The Jefferson's theme (Movin' On Up) is heard over the closing credits.
Lisa and Bart reference This Little Wiggy when Ralph appears as Bart's friend. It seemed Bart forgot about the police master key. However he might have realized about it in the future.
Homer asking the mirror who is the baldest of them all is a reference to Snow White.
Bart is too young to take a flight on his own, he would at least need one adult with him to go.
Part of Bart's pants were a darker shade of blue (because it was wet) but after the scene switched from grandpa it was only one shade of blue.