Accumulate frequent flyer miles so you can either fly free or pay down the cost of a ticket using miles. If you stick to one airline, or an airline alliance, you can more quickly garner enough miles for a free or reduced price ticket. With 27 member airlines, the Star Alliance network has the greatest number of airlines in one group.
Get an airline branded credit card. You can use miles you accumulate on your Delta SkyMiles credit card to pay down the cost of your ticket and, if you are a Delta SkyMiles credit card holder, you can check one bag free. Note that not all flights are "Pay with Miles" eligible, so choose only the ones with that option. With the Continental OnePass Card, you earn miles and can check a bag free on Continental Airlines; a JetBlue Card from American Express lets you earn miles for free JetBlue tickets.
Check airfare comparison sites like Kayak.com. Kayak checks hundreds of other travel sites and find the lowest fares, which may involve flying different airlines for different legs of a trip, or flying into a nearby airport. You can do some of this legwork yourself, but Kayak is a free service and saves you time as well as money. FareCompare and Airfare Watchdog also compare flights on multiple airlines.
Bid for a lower priced airfare at Priceline.com. Once you know the lowest price you can find on a airfare comparison site, you can underbid at Priceline.com and see if they can beat the price.
