Fantasy Planes makes the claim that some of the most interesting airplanes are the ones that never got built, and I can’t say that I disagree. The site has very nice galleries of unusual aircraft that never flew as well as a good collection of links to other sites.
Along that line, The Strange Mechanism Museum has a great collection of images of unusual aircraft, ships, and other vehicles. It appears that the site creator’s first language is not English, but if you ignore the typos etc. the page has a lot of fun stuff to browse through.
