Ok I have always lived in a house with ceiling fans so I never even thought about flight training. Now I live in an apartment and the fans are gone and I have two parrots that are still working on step up training. I am thinking about what I will need to keep them safe as their wings grow out. Does anyone have ideas that could be used in an apartment-- a rental I can't alter? The front door is around a curve which in this case provides a hallway but the back is a large sliding door. I can't put a catch over it--at least I can't figure out what I could do that would not be unsightly and dangerous. I would love a suggestion, and please note I am not a builder so I need something made for me---inexpensively. Thanks for anyone with ideas.