Delta Airlines officials allegedly tried to 'trap' their own flight attendants on a delayed flight to prevent them from walking off after they maxed their weekly working hours.

The incident took place on May 12 on Delta Flight 1990 going from Atlanta to Toronto, where the flight was grounded for three and a half hours following a maintenance problem.

As the airline tried to resolve the issue, an employee in Delta's operations control center sent a message to the Delta gate agent handling the flight warning them to keep the flight door closed to prevent the flight attendants - who they feared had reached their max hours - from walking off.

'Do not open the door flt attendants out of time and none available,' the internal server message viewed by the Huffington Post said.

Delta Airlines allegedly closed the door on their delayed Flight 1990 going from Atlanta to Toronto on May 12, to prevent overworked flight attendants from leaving

The message was sent at 10.19pm and followed up by another message a half-hour later saying: 'Ok...door is not closed by [11pm] Flt attendants walking. We will mostly likely have to delay flight until morning if this happens.'

Someone in the flight tower then responded, 'Copy'. The messages were sent in a internal server for employees.

According to FlightAware, the flight took off nearly three and a half hours after it was scheduled to at 11.27pm and landed in Toronto after 1.30am.

In the end the flight attendants stayed on board and operated the flight, but not without complaints.

A flight attendant listed as 'flight leader' said in the correspondence said they knew that the operations team was trying to 'trap' them on the plane, even though the attendants were willing to work voluntarily.

'Since we are deciding to stay although y’all are trying to trap us on the plane, and now our layover has been shortened and we will be past our duty day, hungry and tired. It would be nice to have a deadhead at some point tomorrow,' the flight leader said.

One flight attendant responded in the server that the airline was trying to 'trap' them even though they were willing to work overtime voluntarily

A 'deadhead' is when a flight attendant or pilot flies as a passenger and gets paid but isn't working.

'We are ready to walk literally, Doing the operation a huge favor,' the flight leader said in a follow up message.

The discrepancy sheds light on just how overworked flight attendants are.

Flight attendant hours vary from airline to airline, but generally when an attendant hits maximum hours for a series of flights, they can't be forced to continue with the next segment of the flight, and if they do, they get paid extra.

Despite having overworked attendants on board, Delta was reluctant to bring in another crew to staff the plane.

Flight attendant duty hours are usually laid out in a union contract, however Delta flight attendants are not unionized.

In this scenario it's not clear if the attendants had the option of leaving.

Delta said that the door on the flight was opened after the maintenance work was resolved and flight attendants could have walked out if they wanted to.

'Operating an airline is a team effort and the guidance shared in this exchange does not reflect the respect and collaboration we expect of our employees when making operational decisions,' Delta said to the Post in a statement. 'Delta’s unique culture is built on supporting one another and that didn’t happen in this case. We have followed up directly with the team members involved to address this situation.'