United Airlines is outsourcing more than 600 jobs at 12 airports around the country to cut costs while adding jobs at other airports.

The outsourced positions include ticket and gate agents and baggage handlers at airports served mostly by smaller United Express flights.

The International Association of Machinists and Aerospace Workers said that it negotiated seniority protection for many of the workers if they relocate, and that job losses will be limited.

United will hire other companies to handle the work at airports in Albuquerque, El Paso and Salt Lake City, among other places.

Under the union contract, United will take back about 400 jobs that had been outsourced at Phoenix, Denver, Honolulu and Dulles International Airport in northern Virginia.