What is the fine-grained topic of the following text: A guest speaker at the “OSHKOSH” AirVenture 2006/2007 event, (world’s largest air show), Michael has developed a number of contacts which have had first hand experience dealing classified “black programs”, including former USAF pilots, retired Naval personnel, and aerospace engineers that have maintained a TOP SECRET SCI security clearance. Only return the topic.
Guest speaker's contacts with experience in classified aerospace programs