Ph.D, Daniel J. Benny 
General Aviation Security [PDF ebook] 
Aircraft, Hangars, Fixed-Base Operations, Flight Schools, and Airports

After 9/11, the initial focus from the U.S. government, media, and the public was on security at commercial airports and aboard commercial airlines. Soon, investigation revealed the hijackers had trained at flight schools operating out of general aviation airports, leading to a huge outcry by the media and within the government to mandate security