The benefit of global airline alliances is sharing revenue and passengers to fill planes.
"Normally, when airlines change alliances, you can no longer earn or redeem miles on the old alliance members," said Brian Kelly, founder of ThePointsGuy.com, a blog and website for maximizing airline frequent-flier miles and credit-card points.
US Airways, however, will retain codeshare - two or more airlines' facilitating a single journey - or frequent-flier program relationships with 12 airlines that are not in Oneworld. Ten were in Star Alliance, and two, Hawaiian and Jet Airways, were not.
Although these relationships may be phased out in coming months, passengers for now will be able to earn and redeem miles for travel with the carriers.
For the majority of the 28 Star Alliance carriers, US Airways fliers will not be able to redeem or earn miles, including on Lufthansa, Asiana, and Swiss Air. Any travel booked with former Star Alliance partners is safe, but passengers won't earn miles for the flights.
"For Philadelphia-based fliers, that could either be a good thing or a bad thing," Kelly said. "It's based on which carriers you fly."
There's one big negative to the change:
British Airways and Iberia Airlines, part of International Airlines Group (IAG), tack on a fuel surcharge when passengers use mileage rewards for flights. The fuel charge can be $500 or more per round trip, even on an economy ticket.
"That will be a shock to US Airways Dividend Miles members, who now don't get hit with huge award fuel surcharges," Kelly said. "You can redeem your miles on British Airways, but then expect to get slammed with a $500-or-more fee."
Kurt Stache, American's senior vice president of alliances, clarified that American did not charge the "redemption fuel surcharge. British Airways does."
Dividend Miles members and AAdvantage members who redeem miles or points on American Airlines or US Airways do not get a fuel fee, he said.
"However, if they choose to redeem their miles on British Airways, British Airways does on certain tickets charge the fuel surcharge," Stache said. "Depending on the cabin you redeem in, and the length of the trip, it can vary."
For now, US Airways will continue to run its Dividend Miles program and American its AAdvantage program. At some point, probably next year, the programs will merge.
US Airways Dividend Miles members "will maintain their tier status, and all qualifying miles previously earned through Star Alliance carriers are safe," the airline said.
Dividend Miles chairman, platinum, and gold members can access nearly 600 airport lounges worldwide when flying on a Oneworld member airline.
"US Airways has codeshare relationships with carriers within Star Alliance and outside of Star," Stache said. "Going forward, some of the Star carrier relationships are ending, like United, Lufthansa, among others. A few will stay on for a while longer. Carriers like Hawaiian, for example, aren't part of an alliance and will continue to have a codeshare frequent-flier relationship with US Airways."
American has partnerships with "many of the same carriers that US Airways does," Stache said. "As we integrate the airlines, the new American will establish relationships with various carriers around world, both within the Oneworld alliance and outside the Oneworld alliance."
US Airways' network will add more than 50 destinations to the Oneworld map, mostly in the United States, but also in Canada and Mexico, along with its hubs in Philadelphia, Charlotte, Phoenix, and Washington's Reagan National Airport.
US Airways will continue relationships with 10 of its Star Alliance partners:
Air New Zealand (ends 6/29)
South African Airways
US Airways also will continue revenue- sharing partnerships with two airlines that are not part of the Star Alliance:
US Airways will join Oneworld, a global airline partnership that includes American Airlines. Members of Oneworld: