A Jetstar flight attendant has told a Senate inquiry that a crew member was ordered to clean around a dead body and managers have shown no concern over staff falling asleep on long-haul flights.

The grounding of the Qantas fleet dominated the day's evidence before the Senate, but a last-minute witness, Sydney-based Jetstar flight attendant Michael Kelly, took the hearing in a different direction.

Mr Kelly testified he and several of his colleagues had been falling asleep on 15-and-a-half-hour return trips between Sydney and Bali.

He highlighted the case of a woman who crashed her car on the way home from one such flight and later committed suicide.

"Because she stopped for coffee to stay awake she didn't receive any assistance from the company because she broke the journey from point A to point B," he said.

He said another colleague was forced to clean an aircraft while the body of a deceased passenger was still on board.

Mr Kelly said he would prefer to work for Virgin Australia because of poor working conditions within the Qantas group.

"A lot of Jetstar employees wish to work for the Virgin group because Sir Richard Branson and John Borghetti take great care of their crew," he said.

Mr Kelly also testified a colleague suffering glandular fever kept working after sending 13 unanswered emails to the company asking for time off.

Earlier, Qantas chief executive Alan Joyce argued his decision to ground Qantas's fleet was justified.

Meanwhile, Jetstar has taken three of its Airbus A320 aircraft out of service over safety concerns.

The budget airline owned by Qantas says it has detected a small amount of movement in the tracks of recently installed seats.

Jetstar says it has cancelled six flights as a precautionary measure.