FORT WORTH, Texas (AP) -- American Airlines and US Airways will begin selling tickets this month on each other's flights, a small step in the airlines' progress toward eventually combining fleets after last month's merger.

The airlines announced a so-called code-sharing agreement on Monday that will initially cover most flights between American hubs such as Dallas-Fort Worth and Miami and US Airways hubs including Charlotte, N.C., and Philadelphia; the US Airways shuttle on the East Coast, and some other U.S. and international routes.

Code-sharing starts Jan. 23 and will expand to all flights on both carriers in the coming weeks, they said.

The arrangement will, among other things, let customers book a single ticket on either airline's website that includes flights on each carrier.

The airlines expect that code-sharing will boost revenue by keeping customers who might otherwise book on another carrier. It is a step in the plan that calls for eliminating the US Airways name in about two years and operating all flights under the American Airlines banner.