US Airways will join oneworld® with effect from March 31, 2014, following completion today of its merger with alliance founding member American Airlines. All its regional affiliates, operating under the US Airways Express brand, will also transition to oneworld at the same time.
Their entry into oneworld with effect from the first flights on March 31, 2014 will follow immediately upon their exit from the Star Alliance with the final flights on March 30, 2014. All parties are taking every effort to ensure that the alliance transition is as seamless as possible for customers.
Until the full integration of American Airlines and US Airways – which will see the combined airline retaining the American Airlines name – US Airways and its regional carriers will operate as oneworld affiliate members, under the American umbrella.
They will offer oneworld’s full range of services and benefits – although some may be phased in shortly after US Airways joins. US Airways, American and their oneworld partners are working to provide the most popular benefits and services on an accelerated timeline.
http://hub.aa.com/en/nr/pressrelease/us-airways-to-join-oneworld-on-march-31-2014