I just flew the Skystreak from Classic Wings and I had a blast. Try your hand at going supersonic, but be careful, the controls will freeze up and the altitude loss in the acceleration attempt might be hair raising. The sound of the sonic boom was reward enough for the download.
http://www.classicwings.net/freeplanes/skystreak/skystreak.html
http://www.classicwings.net/freeplanes/skystreak/skystreak.html