Suggested Military Aviation Websites:

United States Air Force Museum
National Air and Space Museum (Smithsonian)
Aviation History Online Museum
USAAF Resource Center
Planes and Pilots of World War Two
American Aircraft of WWII

or use Google, or another search engine to find your own.

Remember: not all web resources are equal. Cross-checking and verifying data from more than one source is always a good idea. Don't forget to cite your sources. Unless you know the drag/ lift ratio of a P-39 off the top of your head, I would expect to see such data clearly annotated. Consult the APA or MLA if you have questions.

Good Luck! I look forward to reading your findings. Make sure you submit your work before the due date listed in the course schedule.