Pakistan International Airlines (PIA) has ordered an inquiry after two sets of human remains it was meant to repatriate were left in New York.
The two coffins were meant to be flown to Lahore on 28 October but were left behind at JFK Airport by mistake.
It was PIA's last New York-Lahore flight, as it had just suspended the route - so Etihad Airlines stepped in.
PIA blamed ground handling staff but relatives of the deceased have criticised the airline's response.
PIA said it "regrets the inconvenience caused due to negligence on part of the airline's ground handling agency... and expresses its sympathies with the family members of the deceased persons".
One of the families had asked for their relative, Nauman Badar, to be buried in Maryland, while the body of the other man, Nasir Ali, was being transferred by Etihad Airways back to Lahore, PIA's statement added.
Islamic custom calls for the body to be buried as soon as possible.
PIA said it would look after the transfer arrangements, adding that "all expenses will be borne by PIA".
But Hasan Mubarak, a cousin of Badar, told the BBC that no one from PIA had been in touch with family members either in Pakistan or in the US.
Mubarak told Dawn newspaper the family had been "agonised" by the actions of the airline.
He said the body of his cousin had been retrieved by funeral staff at the family's behest, not the airline.
Pakistan's national carrier has suffered a number of adverse headlines in recent months.
In May it said it was taking measures to ensure its planes were not used to carry drugs after heroin was found on two of its London-bound aircraft.
Three months earlier it emerged that seven extra passengers were allowed to stand in the aisles on a PIA flight to Saudi Arabia.
Last year the airline was mocked after employees sacrificed a goat to ward off bad luck following one of Pakistan's worst air disasters.