Racking up airline miles is one of the best ways to save on airfare, and travel credit cards offer a way to earn miles without flying. By signing up for an airline credit card that offers a big signup bonus, you can frequently earn enough miles for a round-trip flight.

While it's easier to earn enough miles for an economy class ticket, you can score superior value when you redeem miles for business class. A round-trip flight to Rome from the U.S. on American Airlines, for example, can cost over $3,500 or just 115,000 American AAdvantage miles plus taxes.

Scoring cheap economy flights is easy with frequent flyer miles, and that's especially true with airlines that offer fare-based redemptions. When Southwest Airlines has a sale, for example, you can frequently book one-way domestic flights for as little as 5,000 miles plus $5.60 in taxes.

If you've made the decision to pick up an airline credit card to earn free airfare, make sure your spouse or partner gets one, too. While not everyone knows this, spouses can get the same credit cards and earn their own signup bonuses, even if they share the same address.

Southwest Airlines offers a trick that can help you score free airfare for a companion for more than a year. If you earn 110,000 miles through flying and credit card signup bonuses in one calendar year, you earn their "Companion Pass" for the rest of the year and the entire next year.

If you want to score amazing airfare deals, make sure to check out SecretFlying.com and TheFlightDeal.com. Both websites let you know about the best deals on airfare, including flights to Europe for less than $400! To take advantage of these deals, you have to act fast.

Recently, the Hopper app announced its intention to offer secret fares. You cannot access these fares online since they are only available on the mobile app, but you could save up to $500 per flight if you find a deal and book right away.

If you want to earn airline miles but aren't sure which airline you want to fly, consider getting a card that earns Chase Ultimate Rewards. This loyalty program lets you book miles through the Chase portal, and you can also transfer points 1:1 to travel partners like Southwest, United MileagePlus, Air France/Flying Blue, and British Airways.

American Express Membership Rewards is another program that lets you book travel in more than one way. With this option, you can book through AmexTravel.com or transfer points to airlines like Air France / Flying Blue, Singapore Airlines, and Delta.

Google Flights makes it easier than ever to compare airfare prices amongst several different airlines. You can also plug in dates and find cheap destinations to visit from your home airport. Best of all, this service is free.

Never forget that every destination has a peak travel time where prices are higher. If you are willing to travel off-peak, however, you can often save big on both airfare and hotels. Crowds will likely be smaller as well, which is always a good thing.

If your flight is oversold and the gate attendant asks for volunteers, consider whether your travel plans are flexible enough to depart on the next flight. If you agree to a bump, you'll be accommodated on the next departure but you can also receive cash or a travel voucher for several hundred dollars.

Because travel agents have access to special fares the general public cannot see, they can often help you save money on hotels and airfare. Consider using a travel agent for your next trip-especially if you're booking a vacation package and need help with planning.

Most people have no desire to take a red-eye or fly at the crack of dawn. If you're willing to fly these super later or super early fares, however, you can often save big. Compare options and be willing to fly at inconvenient times, and you could cut the costs of airfare by hundreds of dollars.

If you're stressed over the prospect of dealing with airline miles and frequent flyer programs, don't be. You could get a cash-back card to rack up money to spend on airfare instead. This strategy is often easier since you don't have to deal with award availability or blackout dates.

If you live near more than one airport, you should check them all each time you fly somewhere. Flying out of a different airport can easily save you hundreds of dollars on certain flights, and that's true regardless of how far away it is.

It's a known fact that weekend travel is often busier and a lot more expensive. Consider flying mid-week for a better deal on airfare and smaller crowds. A Tuesday-through-Tuesday flight is often the cheapest if you can make it work for your schedule.

Websites like SecretFlying.com and TheFlightDeal.com let you sign up for travel alerts from your home airport. By signing up, you'll be alerted when an amazing deal becomes available. Act quickly, and you could easily save hundreds or thousands on your next trip.

Some cards let you earn "miles" that are redeemable for any travel expense. The Capital One Venture Card is a solid option because you earn a big signup bonus plus 2x miles for each dollar you spend. On the redemption side, you can cash in your points for any flight you want at a rate of one cent per point.

Don't forget to consider the discount airlines in addition to major players like American, United, and Delta. WOW Air, Allegiant Airlines, and Spirit are a few discount airlines that offer insanely cheap no-frills flights, albeit with fewer perks and amenities.

Most major airlines offer special deals via social media, but you have to be a follower to hear of these deals first. Follow your favorite airlines on Twitter and Facebook especially, and you're sure to find out about the best deals before anyone else.

If you are able and willing to book a vacation package that includes both your airfare and your hotel, you can often save on both. You can plan using websites like Expedia.com and Travelocity.com to explore vacation packages, but you'll need to price out each component individually to ensure you're getting a better deal. Even better? Book with a travel agent!

The best way to overpay for airfare is to book with the airline direct without comparing options. Make sure you're always comparing airfare among different airlines and with discount travel websites like Kayak.com. This way, you can find the best deal among several different carriers.

Momondo.com lets you search for cheap flights to nearly any destination, including last-minute flights. Plus, you can set up flight alerts so you're notified when a fare suddenly changes. Use this website during your search for discount airfare, and you are sure to find the best deal possible.

Finally, the best deals go to those who are willing to compromise on their dates and destination. Be willing to consider more than one spot for your next trip, then compare prices among all your options. By keeping an open mind, you'll save more on travel over the long run.