Vstol Websites
The Aviation Zone
A comprehensive online aviation resource for military transport aircraft, aerial tankers and fixed-wing gunships.
3,869,832 
$ 240.00
Raymer's Aircraft Design & RDS site
Aircraft Conceptual Design resources for industry, academia, and research of airplane and spacecraft design, including the textbook AIRCRAFT DESIGN: A Conceptual Approach, the RDS design software, the book Simplified Aircraft Design for Homebuilders, Design Short Courses, and aerospace-related books.
8,357,502 $ 8.95