But for those who are frequent fliers, using a credit card associated with one of the airlines will help you rack up miles in a hurry.
Credit card website CardHub has updated its picks of the best airline credit cards, choosing four that have plenty of advantages for travelers.
Frontier Airlines Credit Card
The CardHub editors pick the Frontier Airlines Credit Card as tops in terms of the best initial bonus. Most credit cards will start you off with some miles, assuming you spend a certain amount in the first three months.
For Frontier credit card holders, you only have to spend $500 in the first 90 days. If you do, the credit card will give you 40,000 initial miles, which can be used right away for two round-trip domestic tickets.
There's a $69 annual fee and other cards offer more miles, but CardHub says the low qualification requirement, along with the relative ease in redeeming the miles, makes Frontier a good choice.
Platinum Delta SkyMiles Credit Card
If you travel a lot, you might want to check out the Platinum Delta SkyMiles Credit Card from American Express. Right off the bat you get a $100 statement credit if you make a Delta purchase in the first three months. If you spend $1,000 during that period, you'll get 35,000 bonus miles.
Other perks include a free checked bag on each trip, a free companion ticket each year, and priority boarding. The annual fee is on the high end – $195. However, there are no foreign transaction fees.
AeroMexico Visa Secured Credit Card
You say your credit has a few dents in it? Not to worry -- the AeroMexico Visa Secured Credit Card passes CardHub's test for the best airline card for consumers with below-average credit.
It's rare to find any kind of rewards card for applicants who do not have good or excellent credit histories, but the AeroMexico Card not only does, but offers 5,000 bonus miles and a free companion ticket after your first purchase. There's no annual fee the first year but $25 a year after that.
Rewards aren't limited to airline spending. The card offers two miles for every dollar spent on gas and groceries, one mile per dollar spent on all other purchases, and free checked bags when you use the card to fly AeroMexico. Because it is a secured card, there is a minimum $300 security deposit that is refundable at some point in the future.
United Mileage Plus Explorer Business Credit Card
For consumers who fly more for business than pleasure, CardHub recommends the United Mileage Plus Explorer Business Credit Card. It starts you off with 50,000 bonus miles if you spend $2,000 in the first three months and tacks on an additional 10,000 bonus miles if you charge at least $25,000 to your card.
It also adds two miles per $1 spent directly with United, as well as charges at gas stations, office supply stores, and restaurants.
There is no foreign transaction fee or a first-year annual fee the first year. After that, you'll be charged $95 a year.
There are also regular credit cards that provide airline miles as part of their overall rewards programs. The best overall, says Cardhub, is the Barclaycard Arrival Plus World Elite MasterCard. Its miles can be used with any airline.