US Airways and American Airlines, which are combining their frequent-flier programs, will continue to reward miles for travel based on distance flown, not fares paid.
That benefits leisure travelers, who hunt for bargain fares, in contrast to business travelers, who often book expensive last-minute tickets.
US Airways Dividend Miles members, who fly occasionally, won't notice much difference - they will get a new American frequent-flier number next year. US Airways' most frequent jet-setters, who log 25,000 miles or more a year, will see changes.
The biggest change will be the end of automatic complimentary upgrades for US Airways silver, gold, and platinum customers, the new American Airlines, based in Texas, recently announced.
Only the top-tier fliers - US Airways chairman's preferred and American executive platinum, who fly at least 100,000 miles a year - will continue to get unlimited upgrades from coach to first class on domestic flights.
When American and US Airways combine reservation systems late next year, lower-level elite fliers in US Airways silver, gold, and platinum levels will have to earn, or pay for, upgrades on flights longer than 500 miles.
On trips shorter than 500 miles, all elite levels will still get free upgrades on North American flights.
"It's a more complicated program for US Airways fliers than it was before," said Brian Karimzad, director of MileCards.com, a site that compares travel credit cards and reward programs.
US Airways' elite-level fliers are used to free upgrades on domestic flights of all distances.
"It's a very big change, going from not having to request an upgrade, and not having to use any coupon for an upgrade, to having to earn these coupons or buy the coupons if you don't have enough in your account," Karimzad said.
The new American is generally adapting the American AAdvantage program, which has three levels of elite-status membership: executive platinum (100,000 miles flown annually), platinum (50,000 miles), and gold (25,000 miles).
US Airways has a fourth level, platinum preferred, for customers who fly 75,000 to 100,000 miles annually. That tier will disappear, and those fliers will be mixed in with American's platinum level and US Airways current gold members, who fly just 50,000 miles a year.
In merging the programs, "we came forward with a hybrid," said Bridget Blaise-Shamai, managing director of American's frequent-flier program.
"Today, US Airways Dividend Miles allows all its elite customers to upgrade complimentary on most of their domestic markets, based on space available, and there is a hierarchy," she said.
"American Airlines has more of a hybrid. Our top tier, executive platinum, has unlimited complimentary upgrades [on domestic flights]. Our gold and platinum members use their stickers, or coupons, that are part of a virtual bank. Gold and platinum customers have two ways to pay for their upgrades: buy them for $30 for every 500 miles, or earn them. For every 10,000 miles you fly, you earn four 500-mile trip segment upgrades."
American has 70 million frequent fliers; US Airways has 30 million.
American and US Airways' mileage balances will be combined in the second quarter in 2015, though no date has been set.
For current US Airways dividend miles members who don't have an AAdvantage account, one will be created and their earned US Airways miles will roll over.
Travelers with an account at both airlines will be able to combine their accounts early next year. Their AAdvantage number will survive.
In the short term, American has said it is not following the lead of Delta, United, Southwest, and JetBlue airlines in adopting revenue-based travel rewards programs that favor passengers who spend the most.
"For me personally, as an American Airlines flier, that was the biggest thing," said Brian Kelly, founder of ThePointsGuy.com, blog and website for maximizing frequent-flier and credit-card points. "I'm very relieved that American has decided to keep their program, which I think is one of the best out there."
US Airways and American transport nearly 80 percent of fliers in Philadelphia.