WIll the canon XL lens fit on a canon ae1 camera?

No, the Canon XL lens will not fit on a Canon AE-1 camera. The AE-1 uses the Canon FD lens mount system, while the XL lens is designed for a different system, typically associated with Canon's later models. To use lenses on the AE-1, you'll need to find FD or FL mount lenses that are compatible with that camera's system.