TWO workers contracted by Frontier Airlines in the US were reportedly in a heated argument that turned fatal after another man stabbed his co-worker.

CBS Philadelphia reports that an argument started shortly before 11:30am (1:30am AEST) in a break room for Worldwide Flight Services, an aeroplane cleaning contractor for Frontier Airlines, in Terminal E Philadelphia International Airport.

Philadelphia Police Lt. John Walker said a man turned out a light in the break room, upsetting another man sitting there.

Lt. Walker said a third man then got involved and after some shoves, he pulled out a knife and sliced one of the men across the abdomen.

Media outlets reports that the 28-year-old stabbing victim died on his way to hospital.

"Obviously, it was a pretty sharp object to get through his stomach and obviously hit some vital organs," Lt. Walker said.

The 35-year-old killer and the other man tried to run away after the stabbing but airport police were able to catch them.

They are now both being questioned.

No passengers were involved in the altercation.

Frontier Airlines has so far declined to comment on the case.