- There are two supersonic corridors in Missouri that allow the military national guard and Boeing to test their aircraft. One is along the Mississippi south of St Louis. Every F-15 and F/A -18 aircraft that is built in St Louis is checked out to about Mach 1.6 before delivery. As long as they stay in the corridors, there are very few complaints. **************************************************************************** Our WebPage! Http://WWW.GeoStL.com Mail List Info. //www.freelists.org/cgi-bin/list?list_id=geocaching The SLAGA E-store is closed for image repairs...... ****************************************************************************