It seems like every brand is offering some kind of loyalty card these days. From restaurants to retailers, hotels to hot spots, being a member has its perks. So which U.S. airline offers travelers the best rewards for their loyalty? Here are the top five.

Delta

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Delta’s SkyMiles program is one of the best frequent flyer options out there. Better? It’s free to join. There are no expiration dates for earned points and cardholders earn five miles for every dollar they spend. Delta will also give SkyMiles members 7,500 bonus points for vacation packages purchased on the Delta website.

As an even bigger reward for their most frequent fliers, Delta implemented the Medallion Status program, a tiered loyalty system that offers members waived baggage fees, upgrades and multiplied miles. Medallion Status members can earn up to 11 miles per dollar they spend.

For Delta devotees who want to take their SkyMiles memberships to the next level, there’s the Delta SkyMiles Credit Card. The SkyMiles Credit Card gives users two miles per dollar and one mile for partner purchases from vendors like Lyft, Airbnb, hotels, car rental companies, restaurants and retailers. There’s no cap on the number of miles users can earn and Delta will give users a bonus 60,000 miles with $2,000 in purchases made in the first three months.

Frontier

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Frontier Airlines’ Frontier Miles is another great free program that offers one dollar per mile regardless of ticket price. Like Delta, Frontier has a tiered points system. Elite 50K, for members with at least 50,000 points, gets 50% off a membership to the Discount Den and a 1.25 point multiplier. Elite 100K members get a free Discount Den membership, a 1.5 mileage multiplier, free checked bags and a Family Status Bundle with which families can be seated together.

The Discount Den is an add-on to the Frontier Miles program. It costs $60 per year, offers the lowest fares available and children 15 and under fly for free.

Frontier Airlines World Mastercard is the official Frontier Airlines rewards credit card and offers cardholders perks on flights and other purchases. Cardholders earn five times the miles for purchases made on Frontier's website, three times the mileage on restaurant purchases and one mile per dollar on partner purchases. There are also partnerships with a lot of hotels and rental car companies, so bundling a vacation package would earn cardholders a ton of points. Miles don’t expire as long as the cardholder makes a purchase at least every six months, and Frontier offers 40,000 bonus miles for spending $500 in the first 90 days. Users also get no foreign transaction fees and priority boarding. There is a $79 annual fee.

JetBlue

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JetBlue offers the most flexibility with rewards courtesy of three different loyalty programs — two free and one paid.

TrueBlue is JetBlue’s free frequent flyer program and there are lots of unconventional ways to earn points with the TrueBlue card. The standard reward for flying with JetBlue is three points per dollar, but you receive double the points to if you book on the JetBlue website. Points never expire, can be used for any seat and there are no blackout dates. There is also point pooling as a perk, so if someone on the account buys an exit row seat, the cardholder gets an additional 200 points. Traveling with a pet earns the cardholder another 300 points. Booking a vacation package on JetBlue’s website will give the cardholder a reward of six points per dollar spent.

JetBlue has two credit cards available to users – the JetBlue Card and the JetBlue Plus Card. With no annual fee, the JetBlue Card is definitely handy for those on a tight budget or interested in small vacation perks. The JetBlue Card offers triple times the points for JetBlue purchases, twice the points for participating restaurants and grocery stores, regular points for partner purchases, 50% off in-flight purchases, no foreign transaction fees and 10,000 bonus points after spending $1,000 in the first 90 days.

For those who want a little something extra, the JetBlue Plus Card offers everything that the JetBlue Card does, but with more benefits. The JetBlue Plus Card doubles purchases made on JetBlue.com to six points per dollar, quadruples the $1,000 purchase in the first 90 days to 40,000 rewards points, rewards 5,000 bonus points on the cardholder’s anniversary date, gives $100 credit for vacation package purchases and the first checked bag is free for the cardholder and up to three companions. For just a $99 annual fee, the card pays for itself with a vacation package purchase.

Southwest

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Southwest’s Rapid Rewards is different in that there isn't a set multiplier like the other airlines – they give the buyer options. Rapid Rewards members can choose between the Wanna Get Away?, Anytime and Business Selection options which yield six, ten and twelve points per dollar respectively. There are no blackout dates, unlimited rewards seats and points don’t expire as long as the member is still earning points within a 24-month period.

The Southwest Rapid Rewards Credit Card is consistent with the Southwest brand, charging a $69 annual fee to cardholders. Consider it an insurance plan. There’s no charge for changing your flight. The Rapid Rewards Credit Card rewards 3,000 anniversary points, double the points for every dollar spent on Southwest.com, one point for partner purchases, two free checked bags for every flight and 40,000 points for $1,000 worth of purchases in the first three months.

Spirit

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Free Spirit, Spirit’s frequent flyer program, is unique in that it allows members to earn rewards in many interesting ways that aren’t related to flying. A Free Spirit-er can earn 400 free miles by taking a survey on Spirit.com or by connecting their account to Swagbucks, MyPoints, Vinesse Wine Club and select online games. Members earn five miles per dollar for partner purchases and are partnered with hotel and rental car chains. Members can also add their account number up to 30 days after travel if they were unable to add it during booking.

Spirit also offers a Spirit World Mastercard that doubles rewards miles on every purchase and has no blackout dates on rewards tickets. Cardholders can start redeeming flights at 2,500 points and receive Zone Two priority boarding on all flights. Spirit also offers fraud protection and no foreign transaction fees for just $59 annually. Points never expire and Spirit rewards members with 30,000 bonus miles for spending $500 in the first 90 days.