American Airlines is preparing for some management-level layoffs and buyouts in an effort to slim down five years after its merger with US Airways, the airline told employees on Tuesday.

"As a result of the integration work required, American has more director and above leaders than we require for the long term," said a note seen by CNBC to employees signed by CEO Doug Parker and American's president, Robert Isom.

American Airlines had 126,600 full-time equivalent employees at the end of 2017, a 3.5 percent increase from a year earlier.

Marketing, information technology and revenue management could be among the affected departments. American's unionized pilots, flight attendants, mechanics or the airline's other customer-facing positions, which make up most of its workforce, are not part of the process, the company said.

Reached by CNBC, an airline spokesman declined to say by how much the airline wants to reduce its headcount.