The FAA has proposed levying a $4 million penalty on Spitfire Aviation Services of Fayetteville, Ark., for allegedly conducting at least 798 illegal charter flights between November 2005 and October 2007. Spitfire, which operates a Citation II, King Air 200 and Bonanza, did not hold an air carrier certificate, the FAA said. The agency became aware of the violations through a complaint from a competitor. Spitfire had until early this month to respond to the FAA.