DENVER (AP) — Saying Southwest Airlines is neglecting workers and its customers, baggage handlers are bringing attention to the company's slide in on-time performance as they seek a new contract.

Workers picketed and handed out leaflets to passengers at Denver and 15 other airports across the country Tuesday. On Wednesday, they plan to press their point in an ad in USA Today.

For years, Dallas-based Southwest was the most punctual of big U.S. airlines, but it stumbled after trying to squeeze in more flights into its schedule. Southwest has also prided itself on keeping its employees happy, believing that would guarantee good service for its customers.

"That recipe is kind of gone and it's profits over people and that's not acceptable," said Charles Cerf, president of the Southwest baggage workers' union, Transport Workers Union Local 555, who was picketing in Orlando, Florida.

About 50 percent of the time, Cerf said there is only one worker pulling bags out of the bigger version of the Boeing 737 Southwest now flies even though plane holds 38 more passengers than the previous version, requiring an extra flight attendant. He said that is contributing to the airline's delays and hurting customers.

Southwest was in last place in on-time arrivals among the largest five carriers in 2013 and much of 2014 but topped American and United in October, according to figures released last week. Over the summer it began scaling back its schedule changes and allowing more time between flights.

Southwest spokesman Bob Hughes said the airline has always supported the rights of its employees to express their opinions. He said the number of bags handled by each worker has declined with increased staffing.

"We value our employees and it shows in their compensation," said Hughes, who said the airlines' ramp, operations, provisioning and cargo agents are among the highest paid in the industry.

The workers and airlines have been trying to reach a new contract for over three years and are now in mediation. The union is opposing Southwest's proposal to add part-time workers, which Cerf said would change Southwest's culture.

Workers also staged informational picketing at airports in Dallas; Los Angeles/Ontario; Buffalo, New York; Cleveland; Detroit; Fort Myers, Florida; Indianapolis; Milwaukee; Minneapolis; Pittsburgh; Reno, Nevada; San Diego; San Jose, California; and Seattle.