AirAsia chief executive Tony Fernandes on Tuesday expressed his grief to the relatives of the 162 passengers and crew who were on board Flight QZ8501 after wreckage and bodies were spotted at sea.
"My heart is filled with sadness for all the families involved in QZ8501. On behalf of AirAsia, my condolences to all. Words cannot express how sorry I am," he wrote on Twitter.
Fernandes said he was rushing to Surabaya in Indonesia, where the plane took off on Sunday bound for Singapore and where relatives have gathered.
"Our thoughts and prayers remain with the families and friends of our passengers and colleagues on board QZ8501," his Malaysia-based airline said in a statement.
It said employees of affiliate AirAsia Indonesia, which operated the crashed plane, had been sent to the site in the Karimata Strait where debris was found and would fully cooperate in the investigation.
AirAsia Indonesia announced it would invite family members to Surabaya, "where a dedicated team of care providers will be assigned to each family to ensure that all of their needs are met".
Out of the 162 passengers and crew on board, 155 were Indonesian.
The accident was the third disaster this year involving a Malaysian-owned carrier.
Malaysia Airlines Flight MH370 disappeared in March while flying from Kuala Lumpur to Beijing with 239 passengers and crew.
In July another Malaysia Airlines flight - MH17 - was shot down over unrest-hit Ukraine, killing all 298 on board.
Malaysia's transport minister Liow Tiong Lai said his country "stands in solidarity with the families and loved ones of those onboard (the AirAsia flight) and offers our deepest condolences".
"This is indeed a trying time for those affected and Malaysia is deeply saddened by this tragedy," Liow said in a statement, offering Indonesia all possible help.