You can also go the two-piece 'flight suit' route. As long as, when kitted up, others can't tell it's in two pieces you can go with a black pair of pants and a black shirt of similar material to a flight suit. For quite some time, I simply wore a pair of black slacks and a black dress shirt with the collar tucked in under my armor. I recently swapped the shirt for a long-sleeve under armor heat gear shirt, but when the armor's on, you can't really tell at a glance.