It's the uncertainty that leads to longest wait times. If I have no suitcases to drop off, and it's at a quiet time, then I can arrive half an hour before depa

It's the uncertainty that leads to longest wait times. If I have no suitcases to drop off, and it's at a quiet time, then I can arrive half an hour before departure, breeze through security, and get on the plane. But if I have cases, or security _might_ be long, then I'm having to leave at least an extra half an hour in case of big queues, if not an hour. And that's a time-killer. The "automated bag drop" that some airports do now has really sped things up, but I'm sure some more time could be cut there. Security is the main bottleneck nowadays.