A contract baggage handler who became trapped in the belly of an Alaska Airlines jet on takeoff from Seattle after falling asleep in the plane's cargo hold this week has been banned from all future work at the airline, a company spokeswoman said on Thursday.

The employee of Menzies Aviation, which is contracted to provide ground services for Alaska Airlines, made news on Monday as an unintended stowaway on Flight 448 when he woke up from a nap inside the sealed baggage hold to realize the plane was already airborne.

The pilot of the Los Angeles-bound flight turned the jet around to make a safe but unscheduled emergency landing back at Seattle-Tacoma International Airport after the crew and passengers heard banging from below the cabin and flight deck.

Emerging unhurt from the plane, the wayward baggage handler told authorities he had dozed off inside the front portion of the cargo hold before takeoff.

He later passed a drug test and was released from a hospital where he was taken for evaluation, the airline said.

The worker, who has not been publicly identified, was never in any immediate danger because the cargo compartment where he was trapped was pressurized and temperature-controlled, airline officials said.

But in a panicky 911-emergency call placed after awaking inside the belly of the plane, the worker pleaded with the operator for help, screaming, "I can't breathe," before the connection was lost, according to a recording released by airport authorities on Thursday.

Also on Thursday, a spokesman for Menzies Aviation, a subsidiary of UK-based John Menzies, said the worker remained employed for the time being, pending the outcome of an investigation.

But an Alaska Airlines spokeswoman, Bobbie Egan, told Reuters: "The employee has been permanently banned from ever working again on an Alaska Airlines operation."

She did not elaborate, but said workers are not permitted to sleep on the job. She said coworkers had noticed he was missing before the jet took off and tried calling his cell phone without success, then "figured he had left his shift."

The Federal Aviation Administration is still investigating the incident, a spokesman for the agency said.