Since American and US Airways announced a year ago that they planned to merge, travelers have been eager to see how the airlines will resolve differences in amenities and frequent-flier programs.

The airlines, which completed their merger in December, are finally hinting how they'll settle one difference. In a message to employees this week, American Airlines Group Inc. leaders said they plan to go with American's practice of providing extra legroom with a few seats in the economy cabin, and charging passengers more to sit there.

Passengers willing to pay American $16 to $159 more per flight — up from $8 to $108 two years ago — can get a Main Cabin Extra seat with up to six inches more legroom on most planes. The perk is free for elite members of American's frequent-flier program.

US Airways sells ChoiceSeats. Those are often window or aisle seats near the front of the economy cabin, allowing for a quicker exit after landing, but they have the same legroom as non-choice seats.

American hasn't said how it will install the roomier seats on US Airways planes, which eventually will be repainted in American's colors and logo. It could try to squeeze other rows closer together or use slimmer seats to create more space.

Most big airlines now sell economy-cabin seats with extra legroom. United Airlines calls its offering Economy Plus, and Delta Air Lines sells Economy Comfort seats. They often come with other perks such as priority boarding to ensure that buyers can find room for their bag in the overhead bin.

Travel experts have strategies for snaring good seats without paying extra. Their advice ranges from setting up email alerts with websites such as ExpertFlyer to politely asking the gate agent.