Scooby-Doo and The Ghoul School(1988)
Part of a series of Hanna-Barbera TV movies created in the late 80s, it featured popular franchises like Scooby-Doo, Yogi Bear and The Jetsons.
Scooby Doo and the gang visited a haunted school. After the girls are kidnapped, it's up to Scooby and the gang to save them.
This movie is still available on DVD and Video
This home entertainment trailer was originally posted to YouTube by ScoobyDoovideos123. Note how it frames the older animation with newer images.