Science Buddies: "Ask an Expert"

Hi. I recently got a mentor that is a jet propulsion expert. She asked me to give her a general topic of something I would like to do for science fair dealing with jet propulsion. I want something interesting, yet fairly difficult (or very difficult??). Anyways, I've always been interested in JPL, Boeing, etc. that sparked an interest in jet propulsion as well. However, I am TERRIBLE at coming up with topic ideas. I kind of like the idea of a self-contained propulsion device, but that's one thing I don't know much about. Actually, it seems weird. Haha. I haven't been able to find too much info on it.

Not sure if it helps, but I've recently been reading up on scramjets and JIMO...

Any suggestions for topics? I really need help.

Don't know if we have any rocket scientists on this board. And, besides, you have one as your mentor. You should be running ideas past her. Who better to guide you on a interesting path.