* If you plan to pay in person and with your own bank check, take at least two forms of identification with you like a driver's license, major credit card, or employee I.D. card. Particularly when you purchase tickets far from your home town, airlines, travel agencies and other ticket outlets will want to confirm your identity.

If you paid for your ticket with cash and you have a refundable fare, you can often get an immediate refund from the issuing airline or travel agency. If you paid by personal check, the refund will generally have to be mailed to you.

NOTE: In some cases tickets purchased overseas in foreign currency can only be refunded in that same currency and country, due to foreign government monetary restrictions. Keep this in mind if you are considering buying a ticket in a foreign country.

* When you pay by credit card, your charge account is billed-whether you use your tickets or not. You won't receive credit unless the original unused tickets are returned to the airline. You usually can't get cash refund for a credit card purchase.

* If you buy your tickets with a credit card and then change your flights, the ticket agent may want to credit the amount of the old tickets and issue another set with a second charge to your account. You may want to insist that the value of your old tickets be applied to the new ones, with the difference in price charged or credited to your account.

While this creates a little extra work for the airlines, it prevents double-billing to your charge account.

* There are different rules for different types of airfares. You can purchase discount fares or pay full fare. Check with your airline to find out the rules and cost of different types of fares.

Payment by credit card provides certain protections under federal credit laws. When a refund is due, the airline must forward a credit to your card company within seven business days after receiving a complete refund application. If you paid by credit card for a refundable fare and you have trouble getting a refund that you are due, report this in writing to your credit card company. If you write to them within 60 days from the time that they mailed your first monthly statement showing the charge for the airline ticket, the card company should credit your account even if the airline doesn't. This procedure is particularly useful if your airline ceases operations before your flight.