Demanding better healthcare and employment conditions, hundreds of airline workers, union officials and their supporters called for strikes against aviation-related companies during a demonstration Thursday at Los Angeles International Airport.

The protesters, who marched through the Tom Bradley International Terminal and Terminal 6, demanded action against airline service companies, which they say jeopardize the health and safety of their employees.

Airport police estimated that about 600 people attended the demonstration. Sgt. Belinda Nettles, a department spokeswoman, said no arrests were made and LAX operations were not disrupted. Traffic also moved unobstructed through the terminal area.

The companies in question contract with air carriers to supply thousands of low-level security workers, aircraft cabin cleaners, wheelchair assistants, baggage handlers, cargo handlers and ticket checkers at security stations.

"Enough is enough. We cannot allow these irresponsible contractors to continue to negatively impact the lives of our workers any longer," officials for the Service Employees International Union United Service Workers West said in a prepared statement. The union represents about 4,000 of 8,000 airline service employees at LAX.

SEIU officials have singled out Aviation Safeguards, which supplies more than 470 workers to airlines at the nation's third busiest airport.

Company officials said their employees voted in December to reject or decertify their collective bargaining agreement with the SEIU before its expiration date. Since then, hourly wages have improved for the vast majority of employees, they said, and workers can choose the type of healthcare plan they want.

Alejandra Valles, a vice president of SEIU United Service Workers West, said demonstrators voted Thursday for rolling strikes against the company. She added that employees of other airline service firms could walk off their jobs in a sign of solidarity if a strike occurs.

Aviation Safeguards simply terminated its labor contract and no longer provides healthcare plans for families, Valles said. The company, she said, has not provided proof of the decertification vote and has refused to participate in proceedings before the National Mediation Board, a federal entity that handles labor disputes.

Company officials assert that there is no legal requirement that they participate in mediation board hearings. Records of the decertification vote, they said, are available for union officials to view at the company's offices.