Q. So far, most of the fares you advertise seem to encourage air travel for short periods of time. Since air travel is so very destructive to the environment, why not list low fares that at least allow someone to stay where they are for longer, thus getting more “trip” for the exorbitant environmental cost?

A. Many of the fares listed do allow for longer stays, though the sample dates we use when listing fares are often for week-long stays. The only reason for doing this is that most Americans are given such limited vacation time, the average being just 10 days, with 2 weeks considered generous by most employers.

There are steps travelers can take to reduce their carbon footprints, such as flying during the day, booking economy seats (smaller seats, less fuel), and calculating emissions per flight and contributing an equal amount to environmental causes.