A passenger has spoken of the "violent death" of a 24-year-old man on a flight from Portugal to Ireland.
The dead man, believed to be Brazilian, suffered an apparent seizure and collapsed, forcing the Aer Lingus service from Lisbon to Dublin to divert to Cork Airport on Sunday evening.
A post-mortem examination is to be carried out to determine the cause of his death.
A Portuguese woman in her 40s was arrested on suspicion of drugs offences after the flight landed when a quantity of amphetamines was discovered.
It is not clear if her arrest is linked to the man's death, but gardai are investigating if the woman was travelling with the dead man.
John Leonard from Cork was on the flight and described the scene after the man first appeared to suffer a seizure and then had to be restrained at the back of the plane before collapsing.
"Horrible. I would say a very violent end - to die that way in the back of an aeroplane, it's not right. It was not very pleasant at all," he said.
One man who attempted to restrain the passenger was bitten on the arm.
Mr Leonard told PJ Coogan's Opinion Line on Cork's 96fm two nurses and a doctor tried to resuscitate the man.
The captain of the flight had asked if there were any medics on board.
"After that it got worse I would say, his seizure seemed to get worse. He was actually on the ground shaking violently," Mr Leonard said.
"The noise he was making was like something I have never heard before.
"It's not something you'd hear everyday. It was like deep anguish is the best way I could describe it, very, very troubled. Not screaming in a sense you know if you'd hurt yourself or something, just a very guttural, from deep within him."
The other 167 passengers on flight EI485 were kept on board for two hours after it landed at 5.40pm before being interviewed by gardai and offered bus transfers to Dublin.
Mr Leonard said passengers remained "extraordinarily calm" but were in shock following the incident.
Aer Lingus described the incident as a "medical emergency".
The post-mortem examination is to be carried out in an attempt to establish if the man suffered a seizure or had an underlying medical condition or if there was another reason for his condition.
The arrested woman was being questioned at Togher Garda Station in Cork city.
