For a science project you could talk about the different types of jet engines. For example you could talk about how commercial jetliners started with the turbo-jets, then they went on to turbo-fans. Then you could build onto the turbo-fan and explain how the high bypass ratio turbo-fan works. I won't get too technical here, just a rough idea. Good luck, hope this helps!
Two A-4's, left ten o'clock level continue left turn!
Or how about a project centered around the future of commercial aviation powerplants....the ramjet engine? Should make an interesting project and there are tons of sources freely available...from the JPL to NASA!