Zack's hot air balloon was a red and yellow hot air balloon owned by Norbert "Zack" Van Houten.
Milhouse and his uncle Norbert decided to flew away in a hot air balloon. When Bart learned it, he caught a rope and climbed up to the basket. They were flying together, but when the balloon flew above an abandoned island, it was hit by a nature-made hang-glider, ridden by Kirk and Luann Van Houten who tried to escape from the island. They all then fell down.