This is crucial if you're connecting anywhere in the middle of the country between November and February, a recipe for extended delays and cancellations. When you learn your flight is canceled -- or delayed to the point of missing a connection -- don't get in the sometimes-miles-long line at the customer service desk. Instead, call the airline's customer service number. Even if you end up holding for an hour, you can spend that time enjoying a lovely beverage or chicken dinner until the next available agent takes your call.
Airport drop-off lines
These typically aren't horrendously awful, but when it's bad -- as around rush hour, or the holidays, or holiday rush hours -- it's the absolute pits. To save yourself (and whomever is picking you up) an undue amount of driving stress, get dropped instead at a nearby hotel and hop on its airport shuttle. Or, if you're arriving, take said shuttle to an airport hotel and have your buddy meet you there. If a train goes to the airport, but not to the part of the city you're heading to, take it one stop to the nearest station and get picked up there. Crunched for time? Have your driver drop you at the less busy deck -- at arrivals, say, for your 8am departure flight -- and then jog up the escalator to join the party already in progress.