Riddle me this - Bat-Shit for brains ; if a large commuter airplane is flying at 35,000 ft - and is creating a "Condensation Trail" behind it , five times the length of the plane,which is normal , on some days - and another commuter airplane is flying above the at 50,000 ft creating a "Chemical Trail" that goes completely across the skies. "Why" then doesn't the "Soo Called" horizon to horizon "Vapor Trail" vanish at 35,000 ft like the lower altitude plane ??? Start with this ; go to the mirror and ponder at stupidity for a while. When you figure this out , THEN - you can go outside and play in the falling aluminum vapor. "SHILL".