Busy entrepreneurs rarely have time to shop online for airfare deals and sometimes end up paying too much. Follow these rules next time you book a ticket, and you'll save--or at least feel confident you covered all your bases.

  • Learn the range. Once you know your travel dates, check fares for several days at travel agency sites like Expedia, Orbitz or Travelocity. Fares can vary greatly from day to day based on demand. Once you know the range, you'll feel more confident in your final decision.
  • Dig deeper. If you live near a city served by JetBlue or Southwest, check their websites, because these carriers don't participate in the travel sites listed above. Another option: new airfare meta-search engines like Kayak.comor SideStep.com, which search various sites for low fares, including travel-agency, last-minute and low-fare airline sites.
  • Know time limits. If you can book during a fare sale, do so as early as possible, since airlines only offer a handful of seats at the advertised fares. If there's no sale, keep in mind that the best deals are for those who book at least 21 days in advance. After that, fares increase at 14, seven and then three days ahead.
  • Adjust your schedule. Cheap fares are more plentiful on low-demand days like Tuesday, Wednesday and Saturday. You're also more likely to find deals during slower travel times like January, February, September, October or the first two weeks of November or December.
  • Book on airline sites. Once you've found an acceptable fare, use the airline site to book. This way, you earn frequent-flier mileage bonuses.