This summer, airlines are flying more planes and filling more seats on each flight. Add the potential for sudden storms and you have a recipe for stress.

Things will go smoother if you fly nonstop or build in a cushion for catching a connecting flight. It pays to travel mid morning (after the business-class rush) to avoid problems that ripple through the system as the day wears on. And using smaller airports can help. For the on-time history of specific flights, check FlightStats.com.