America West and US Airways have finalized their merger and begun operating as a single carrier.

Flyers should continue to book directly with US Airways or America West as they did before the merger. The airlines’ Web sites will operate separately in the short term, as will the two airlines` reservations systems.

While the merged airline will operate under the US Airways name, America West and US Airways will maintain separate operating certificates for approximately two to three years. Once FAA) approvals have been granted, the two airlines’ operating certificates will be combined onto one.

America West and US Airways have announced details of immediate changes to FlightFund and Dividend Miles resulting from the merger. A new program, which will launch in spring of 2006, will retain the name Dividend Miles. Members of FlightFund and Dividend Miles are now able to redeem and earn miles on flights operated by either airline, and their outstanding mileage balance will be automatically combined and integrated into the new Dividend Miles program in spring of 2006.

Other changes have been implemented. For starters, a new four-tiered elite program will be put in place for both programs.

The entry-level elite threshold will be set at 25,000 miles. Benefits include a 25-percent earning bonus, unlimited upgrades on full fares confirmable anytime, and unlimited upgrades on discounted fares confirmable up to two days in advance.

Higher tier thresholds have been set at 50,000, 75,000 and 100,000 miles. America West Platinum Elite members will be elevated to Chairman’s Elite status by Feb. 28, 2006.

Lower-level awards (FlightFund’s 15,000-mile short-hop and Dividend Miles 20,000-mile coach saver) are history. All awards will begin at 25,000 miles.

The Saturday-night stay requirement for Dividend Miles award travel will be discontinued.

A 500-mile bonus for booking online is available at either airline’s Web site.