While you can earn airline miles by flying, the fastest way to rack up miles is by signing up for an airline credit card. Many co-branded airline cards offer signup bonuses worth 50,000 miles or more after you sign up and meet a minimum spending requirement.

Most airlines offer online shopping portals that can help you rack up miles even faster. With American AAdvantage shopping, for example, you can earn extra miles when you shop online at stores like Kohl's, Macys, and eBags.com.

While frequent flyer programs award loyalty with airline status, more miles earned, and extra perks, these benefits are rarely worth it. If you remain loyal to a single airline, you will pay more for airfare over time. You're a lot better off searching for the best deal when you pay for airfare regardless of whether you have status or not.

Many airlines open up greater award availability during off-peak travel times, making it much easier to redeem your miles when you want. If you've been struggling to find an award seat on a flight you've been eyeing, shopping outside of peak season is likely your best bet.

Although it's not easy, you can occasionally earn airline status without flying a single mile. If you have Platinum Elite Status with Marriott Rewards, for example, you receive complimentary United MileagePlus Premier Silver Status via the two program's joint venture, Crossover Rewards.

If your flight is overbooked and you get bumped or volunteer to move to the next flight, you can get a travel voucher or cash-even if you paid with miles. If you're flexible on your arrival time and can stand getting bumped, this is a great way to get a free voucher for your next flight.

Newer rules from the Department of Transportation have made it so you can cancel any flight within 24 hours and get a refund-even if your flight is "nonrefundable." Fortunately, many airlines, including American Airlines, apply this policy to tickets purchased with miles, too.

While airline credit cards make it easy to rack up miles via signup bonuses, they are rarely the best option for everyday spending. Most airline cards offer only 1 mile for each dollar you spend on regular purchases, after all.

If you've been led to believe that a certain airline or frequent flyer program is always best, you've been led astray. The reality is, there are numerous airline and travel credit cards that let you rack up miles, and you can sign up for all of them if you want.

Some travel credit cards like the Chase Sapphire Preferred let you rack up points that transfer to several different airlines. With cards that earn Chase Ultimate Rewards, you can transfer points 1:1 to airlines like Southwest, United MileagePlus, Singapore Airlines, British Airways, Air France, and several others.

While frequent flyer programs probably wish you'd forget, you can earn many of the same credit card bonuses over and over again. Chase Ultimate Rewards cards let you churn bonuses every 24 months, and cards offered through Citi let you earn a bonus within their programs within 24 months of opening or closing a card in the same family.

Flexible travel programs like Chase Ultimate Rewards let you pool your miles before you transfer them to airline partners, but frequent flyer programs themselves don't allow this option. For this reason, you're better off earning flexible points until you're ready to use them.

You may not be able to transfer your miles to other people, but you can redeem your airline miles for a flight for anyone. Many people believe you can only use your miles to book flights for yourself, but this just isn't true.

While not all programs offer this option, some programs like Chase Ultimate Rewards let you pool your points with a spouse or partner. Having this option makes it easy for to rack up more miles and earn twice the signup bonuses then pool your points for superior travel options.

Even if your airline miles are safely in your account, the frequent flyer program they belong in still owns them. This means that a program like United MileagePlus can revoke your miles if they believe you've violated their terms and conditions.

It isn't always advertised, but you can often redeem miles from one frequent flyer program with another airline. This is typically possible if you utilize an airline's partners. For example, you can redeem British Airways Avios for American Airlines flights.

Frequent flyer programs occasionally have sales, and those sales can benefit you if you pay attention. For example, Air France Promo Awards let you fly international in business or economy for up to half off.

While most people envision scoring a "free flight" in economy, you can redeem miles for a fancy flight in first class. You'll just need to fork over more miles to do so, although the number of miles you'll need varies by program.

Many airlines offer dining programs that let you rack up additional points with frequent flyer programs. Southwest Airlines and American Airlines offer the most popular options, making it easy to rack up miles without ever flying if you're willing to dine in participating restaurants.

Some airlines offer unlimited award availability that makes it easy to find a seat on any flight. Southwest Airlines is the most popular for this, as they promise that any seat on a plane is yours if you have the miles or the cash to book.

Another perk that comes with Southwest Rapid Rewards program is the fact you can pay fewer miles for a flight when prices go down. Thanks to their generous rebooking policy, you can also exchange your flight and get a refund of miles if prices go down.

Certain co-branded airline credit cards let you get a free checked bag for free, and some extend the perk to other travelers on your itinerary. The Citi AAdvantage Platinum Select MasterCard is popular for offering this benefit to cardholders.

A mile is a mile is a mile, right? Wrong. Because each frequent flyer program works differently, what each mile is worth can vary drastically. Make sure to research how many miles a flight you're interested in will cost before you start accruing them.

Frequent flyer programs like British Airways Executive Club and United MileagePlus let you redeem your airline miles for items other than airfare. You may be even able to redeem your miles for hotel stays or gift cards.

Finally, don't forget how fuel surcharges can ruin your dream of "free travel." Certain airlines and itineraries are awful when it comes to fuel surcharges, including British Airways flights with routes that pass through London. Make sure to explore fuel surcharges for different destinations before you book your next flight.