Indonesia air traffic control lost contact with AirAsia flight QZ8501 bound for Singapore from the Indonesian city of Surabaya on Sunday morning.
Search and rescue operations have begun, AirAsia Indonesia said on its Facebook page.
The carrier released a statement listing 155 passengers on board, with 138 adults, 16 children and one infant. Also on board were two pilots, four flight attendants and one engineer.
The nationalities of the passengers and crew onboard include one Singaporean, one Malaysian, one French, three South Koreans and 156 Indonesians.
The aircraft lost contact with Jakarta air traffic control at 7:24am local time, 42 minutes after departure and an hour before it was scheduled to land in Singapore, and reportedly while it was flying over Pulau Belitung.
The captain in command had a total of 6,100 flying hours and the first officer a total of 2,275 flying hours, said AirAsia.
The aircraft, which underwent its last scheduled maintenance on 16 November 2014, was on the submitted flight plan route and was flying at 32,000 feet before it asked to fly at 38,000 feet to avoid clouds, Reuters reports.
QZ 8501 was between the Indonesian port of Tanjung Pandan and the town of Pontianak, in West Kalimantan on Borneo island, when it went missing.
The Singapore air force and navy have offered help to Indonesia authorities and have put two C130s on standby.
Singapore Prime Minister Lee Hsien Loong has also commented on the situation on both Facebook and Twitter.
AirAsia has established an Emergency Call Centre that is available for family or friends of those who may have been on board the aircraft. The number is: +622129850801.
AirAsia will release further information as soon as it becomes available. Updated information will also be posted on the AirAsia website, www.airasia.com.
Changi Airport has also set up a Relatives’ Holding Area (RHA) at Terminal 2 Arrival Hall to provide assistance to next-of-kin (NOK) of passengers onboard the flight.
(Correction: This article initially identified the aircraft as an A380. It is an A320.)