United Airlines is outsourcing 15 jobs at Charleston International and several hundred more at 11 other airports to save money.

The airline said it told the 600 total affected workers Monday of the decision, which had been expected since May. They include ticket and gate agents and baggage handlers at airports served mostly by the commuter service United Express.

"This is a difficult decision, but we need to ensure that our costs are competitive," United spokeswoman Christen David said in a written statement to The Post and Courier.

Locally, United has 14 daily nonstop flights on small jets to Chicago, Houston, Newark and the Washington, D.C., suburbs. That number includes service previously offered by Continental Airlines, which merged with United in 2012.

The International Association of Machinists and Aerospace Workers said it negotiated seniority protection for many of the affected workers if they relocate. Still, union spokesman James Carlson called the outsourcing a "race to the bottom. How can you compete with vendors paying $12 an hour?" Carlson said United's top pay for the jobs being outsourced is about $24 an hour.

United has been serving Charleston International since June 1984.

Elsewhere, the carrier will hire outside firms to handle the work at airports in Albuquerque, N.M.; Buffalo, New York; Charlotte; Columbus, Ohio; Des Moines, Iowa; Detroit; El Paso, Texas; Sioux Falls, S.D.; Wichita, Kan.; Pensacola, Fla.; and Salt Lake City.

David noted that the carrier is bringing about 400 jobs in house at four other U.S. airports.

United is owned by Chicago-based United Continental Holdings Inc., which lost $609 million in the first quarter. The airline employs about 87,000 workers overall, according to FactSet.

The Associated Press contributed to this report.