It all depends when you fly and who you are flying with. Airline-wise, Southwest has the longest lines on average. Sometimes their lines are so long, people mistake them for the Security Line! The airport check-in area is relatively small, so security lines appear long when they go out into the street.. but I would say the wait for that would be, at most, 45 min. In terms of airlines, Southwest has the longest, then USAir/NWA/Continental, then Delta, then UA/AA/etc on the shorter end.