Freedom of Information Act Documents--This is a government sponsored site, where the most frequently requested FOIA documents are posted online. It has several catagories, and in the UFO section, there are more than 250 documents(most of them several pages long). This site is definitely worth a look, even if it's only a brief stop.
FlightSim.Com--One of my favorite simulators is Microsoft's Flight Simulator 98. It's a really realistic flight sim with excellent graphics. One of the neatest features is the ability to add on planes from around the web. I've seen lots of different airships, ranging from attack helicopters to spy planes and even a UFO! This site has a tremendous airplane library, and I'd encourage all the flight sim fans to take a look at it.