One transgender barista said his supervisors kept writing “Jessica” instead of Jay on his work schedule.

They stared at his stubble and frowned at his deepening voice. A manager even laughed when he told her to stop referring to him as “she,” said the barista, Jay Kelly, who works at a Starbucks at Orlando International Airport in Florida.

“It’s like a bullet to my heart,” he said. “They look at me like I’m disgusting or like I’m not human or a type of animal that doesn’t belong in that airport.”

Mr. Kelly, 25, is one of some 300 employees who responded to a union survey about conditions working for HMSHost, a travel food service company that has long operated Starbucks and other coffee shops in airports nationwide. His allegations and others’ — including that dozens of employees were told to speak English — were made in a report the union released amid tense negotiations with HMSHost, and as labor groups reach out to marginalized people to increase their membership.