Probably those sites were build with expired domains that still had a high pagerank. Using hidden links like that guy does "font size=1" is not working anymore. If search engines are going to ban those sites because of hidden links it could harm the FYC tours he is linking to i guess....
Here is an old version from one of the sites :
http://web.archive.org/web/200606130...airmuseum.com/
I must say, he seems to maintain those pageranks pretty well