Back to the OP, my cousin is a pilot for Delta. He indicted that lines depend on airport location, time of day, day of the week, etc. He said that the biggest problem has been the fees for checked bags, because everyone tries to dodge the fees by bringing more on in the cabin, which means a backup at the xray machine. Get rid of fees (fat chance) and the lines speed up. Otherwise, you need to add more xray machines, not just people.