APR (Annual Percentage Rate)
Most airline credit cards will start off with 0APR or very low APR, but you will need to compare how long this introductory APR last. Some credit cards offer 0 APR on transfers and balance for a period of one year while others do not.
Airline limitations
Some airline credit cards limit you to traveling on only certain airlines. So when comparing cards make sure the airline you fly on frequently is allowed. You also need to check and compare cards to see which airline card offer the best rewards or rebates.
Miles
Points and rewards on airline credit cards are dependent on the number of miles traveled. Most airlines allows one mile per dollar spent, but a few airlines have different rates.
Blackout dates
Blackout dates are times when you cannot earn points if you fly. These are generally times of high volume such as holidays when many persons travel by air. This is an important factor to use when comparing credit cards. If your main time of traveling is during peak travel season selecting a card with blackout dates will earn you no points.
Ways to earn points
Credit cards that are airline specific generally offer users more ways in which to earn miles and rewards, so this should be looked at when comparing cards.
If the credit card is a frequent flyer card, different issues may come into play such as, annual fee (which is sometimes absent from regular airline credit cards). Despite this however, if you travel with a particular airline more often than not, getting an airline specific card may prove to be the best choice overall.
To compare airline credit cards, Eric Wasselman recommends Find Credit Cards. Please see www.findcreditcards.org/type/airline.php for more information.