Frequent Flyer Program

A frequent flyer program is an airline's loyalty program. Members earn miles or points when they fly and when they spend with partners. They then trade them for award seats and upgrades. The most frequent flyers also climb elite tiers with extra perks. Behind that sits a second business: the airline sells miles to banks and other partners for cash. The guide to the best airline loyalty programs compares ten of them.

How does a frequent flyer program work?

Members earn on the airline's own flights and on partner airlines. They also earn with partners such as card issuers and hotels (Delta 10-K). The miles come back as award trips, and in large numbers. In 2025, award trips made up 12% of Delta's revenue miles flown, from about 35 million award tickets (Delta 10-K). At United the share was about 10.3% (United 10-K). At American it was about 9%, and members cashed in about 18 million awards of all kinds (American 10-K).

Seats for awards on partner flights are capped. American offers travel awards on every flight it runs. On partner flights, the seats are capacity controlled (American 10-K). So a program is worth what its miles can buy: how fast they build up, and how easy they are to spend.

How are miles earned: revenue-based or distance-based?

Revenue-based earning ties miles to the fare paid. Delta gives general members 5 miles per dollar of base fare and carrier surcharges. Diamond Medallion members get 11 (Delta). Air Canada moved Aeroplan to this model on January 1, 2026. Members now get 1 point per $1, and up to 6 with top status (Air Canada).

Distance-based earning ties miles to how far the member flies, scaled by fare class. Aeroplan still uses it on partner flights when another airline issued the ticket (Air Canada). On tickets Air Canada issues itself, members earn by spend even on partner flights (Air Canada). Delta went the other way on one partner. For tickets issued from September 10, 2026, Delta tickets on flights sold under Aeromexico's code earn a share of distance flown (Delta). Economy in B, M or U class earns 100% of the distance. Business in J earns 200% (Delta). The distance-based earning entry covers the mechanics.

For illustration, take two tickets on the same 2,000-mile route, one at $250 and one at $900 in base fare and surcharges. Under Delta's revenue rule, a general member earns 1,250 miles on the first and 4,500 on the second. On a chart that pays 100% of distance, both earn 2,000. Revenue-based earning issues 5 miles per dollar on both tickets. Distance-based earning issues 8 miles per dollar on the cheap fare and about 2.2 on the pricier one. Each mile is a liability, so revenue-based earning keeps the cost of miles in step with the fare. The fares here are assumptions.

How do co-brand credit cards make money for airlines?

The bank buys miles in bulk and hands them to cardholders as they spend. Delta's cash sales from marketing deals were $8.0 billion in 2025, substantially all from American Express (Delta 10-K). Delta expects American Express payments, $8.2 billion in 2025, to reach $10 billion over the next few years (Delta 10-K). American took in $6.2 billion from co-branded card and other partners. Citi became its sole U.S. card issuer in 2026 (American 10-K). United sells MileagePlus miles to Chase, and its 10-K gives no cash total for the deal (United 10-K).

Each sale is split into parts. At Delta, the travel part is deferred until the miles are used and the flight is flown. The brand part is booked as the miles are delivered (Delta 10-K). American splits each sale into a travel part and a marketing part, and books the marketing part in the period of the sale (American 10-K). That split is why a card deal adds revenue before a member ever flies.

Small changes in the estimates move real money. American says a 10% rise in its estimate of miles never used would have added about $140 million to 2025 revenue (American 10-K). A 10% rise in the price it puts on a mile would have cut revenue by about $155 million, since more of each fare is deferred (American 10-K). Delta says most new miles have been used within two years of being earned (Delta 10-K).

Debt can tie a program's hands too. Delta's SkyMiles loans limit program changes that would put repayment at risk (Delta 10-K). The airline loyalty economics guide covers breakage and deferred revenue in depth.

How do alliances and partner settlement work?

Alliances link programs so members can earn and spend on many airlines. At United, deals with Star Alliance members let miles flow both ways. They cover lounge access too (United 10-K). American says oneworld has 15 airlines and links their programs (American 10-K). Delta lists 17 other SkyTeam members (Delta 10-K).

Every cross-carrier earn or redemption moves money. Alaska Air Group's 10-K sets out four flows (Alaska 10-K).

• Its member earns on a partner. The partner pays Alaska an agreed fee, deferred until the points are used.
• Its member redeems on a partner. Alaska pays the partner an agreed fee.
• A partner's member flies Alaska on points. The partner pays Alaska, and Alaska books it as fare revenue when they fly.
• A partner's member earns on an Alaska flight. Alaska pays the partner and books a commission.

In 2025, Alaska booked $255 million for points its members used on partner airlines (Alaska 10-K). Delta and American both sell miles to other airlines as well as to other partners (Delta 10-K, American 10-K). So settlement is a ledger job. Each partner rate, fare class and reversal has to match up.

How GRAVTY handles frequent flyer programs

GRAVTY runs frequent flyer program management on one platform, from miles and tiers to fare classes and accrual rules (GRAVTY for airlines). Codeshare, interline and alliance rules run in the same place, including retro claims. Co-brand, hotel and retail partners are onboarded, invoiced and settled in the platform. Finance tracks liability and breakage with IFRS-compliant reporting. Riyadh Air launched with loyalty live on day one and reached 1 million members less than a year after launch. WestJet cut its year-end rollover from 10 days to 28 hours after moving off Siebel. GRAVTY runs 500M+ members in production on a 99.99% uptime SLA.

Frequently asked questions

Is it free to join a frequent flyer program?

Yes. A SkyMiles account at Delta is free, and Delta uses it to give customers free Wi-Fi on board (Delta 10-K). American made free Wi-Fi exclusive to AAdvantage members from January 2026 (American 10-K).

Do frequent flyer miles expire?

It depends on the program. Alaska's points never expire (Alaska 10-K). At American, miles stay live as long as there is some qualifying activity once every 24 months. They also stay live while the member is the main holder of an AAdvantage co-branded card (American 10-K).

How do airlines value a mile?

Airlines value a mile at the price of the ticket it replaces, less the share of miles that will never be used. Delta calls this equivalent ticket value, adjusted for breakage (Delta 10-K). United bases it on the past 12 months of similar fares used to settle award trips (United 10-K).

How much of an airline's revenue comes from its loyalty program?

In 2025 it was about 16% at Alaska Air Group (Alaska 10-K) and about 12% at Delta. Delta's loyalty travel awards and loyalty program revenue came to about $7.6 billion, out of $63.4 billion in total (Delta 10-K). Partner cash arrives first, and the travel part is booked later, when members fly.

Can you earn miles on one airline and spend them on another?

Yes, when the two airlines are partners. American members earn on any oneworld airline. They can also spend miles on partner flights, where award seats are capped (American 10-K). Delta members can spend miles on other airlines in its program too (Delta 10-K).