Air surveillance is not common, but it is used occasionally on the interstates. There was an article in the newspapers a couple of years ago describing the surveillance. I wouldn't spend a lot of time looking up in the sky, though. The bigger problem in Virginia is that radar detectors are illegal, and the state police use mobile instant-on radar. Not to mention undercover cars. It used to be all you had to look for were rooftop bubblegum machines and Crown Vics. Now literally any recent-model car, SUV, or truck could be an undercover police car, especially in the populous areas like Fairfax County. I can't speak for the more remote areas; perhaps someone else can.