When Buddy is getting ready to run the obstacle course, he is introduced as Buddy Framm and his coach as Noah Framm. Noah is Patrick's son, so his last name would be Sullivan and not Framm.
Only 3 hits are allowed in volleyball, yet Buddy's team used 4 hits to get their 24th point in their final game.
After scoring the 24th point, Bud's team should serve the ball, but in the movie the other team serve.
When Air Bud escapes from the bad guys with the jewel, he has it in his mouth. Once he reaches the merry-go-round and changes the speeds on it, the jewel is gone. When he leaves he has the jewel in his mouth again.