I'm a Systems Engineer for a Defense Company (armored vehicles - but not the M1 tank) living in South Central PA. Occasional travel to offices in MN and CA. I'm Hilton Diamond but am struggling to maintain Silver on US - many more nights than flights... US is officially a "preferred carrier" but we lost our corporate discount this year due to significantly reduced travel on US post 9/11. I usually fly UA (by choice) due to the fare differential and get US miles.