A search and rescue operation is underway after an AirAsia flight from the Indonesian city of Surabaya to Singapore with 162 people onboard lost contact with air traffic control on Sunday.
The passengers onboard the flight include 138 adults, 16 children and one baby, and seven crew.
Reports said there were 149 Indonesian passengers onboard, three South Koreans, one Briton, one Singaporean, and one Malaysian. No Australians were said to be on the plane.
A news conference was due to start at 4pm AEDST at Surabaya airport. Airport officials and spokespeople from AirAsia and the Indonesian search and rescue agency Basarnas, and the Indonesian air force will address it.
Transport Ministry official Hadi Mustofa said the aircraft, flight number QZ 8501, lost contact with the Jakarta air traffic control tower early Sunday morning. AirAsia said this occured at 7.24am local time (11.17am AEDST).
The plane departed at 5.35am Indonesian time (9.35am AEDST) and was scheduled to arrive at 8.30am Singapore time (10.30am AEDST).
Mr Mustafa said the last communication was from the pilot asking for permission to change the height from 32,000 to 34,000 feet in the Kumai Strait near Belitung due to bad weather.
A crisis centre has been set up at Surabaya airport and relatives have begun arriving to tearfully view a full list of names of those who were on the flight.
Indonesian vice-president Jusuf Kalla tweeted: "We pray together with hope that the AirAsia plane QZ8501 SBY-Sin, which lost contact, is soon found and all passengers and crew have survived."
"AirAsia Indonesia regrets to confirm that flight QZ8501 from Surabaya to Singapore has lost contact with air traffic control at 07:24hrs this morning," the airline said.
"At the present time we unfortunately have no further information regarding the status of the passengers and crew members on board, but we will keep all parties informed as more information becomes available."
Shortly after the airline announced the plane was missing, it changed its Twitter and Facebook profile pictures, removing its red and white logo and replacing it with a grey and white one.
"At this time, search and rescue operations are in progress and AirAsia is cooperating fully and assisting the rescue service," the airline said.
"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."
The head of the rescue operation from the Indonesian search and rescue agency said there were three possibilities when a plane lost contact at the height it did: engine failure, that it had ditched over the sea, or was diverted to another airport.
The other airports in the region have been contacted, but have no record of a diversion, he said.
Airforce spokesman Marsma Hadi Tjahjanto confirmed the air force was using the last point of contact to conduct an air search. He said the air force radar recorded the weather at the time as cloudy.
Indonesian aviation expert Gerry Soejatman tweeted that the Indonesian Air Force had dispatched a 737-200MPA to search for the missing flight, and had cited the weather in the area as "challenging".
The AirAsia aircraft that is missing is an Airbus A320-200 with the registration number PK-AXC.
AirAsia was embroiled in controversy earlier this year after publishing an article in their in-flight magazine claiming their planes would "never get lost".
The airline was forced to withdraw the Travel 3Sixty magazine from circulation in April after the comment sparked outrage due to the disappearance of Malaysian Airlines flight MH370 in March.
The article told travellers "Pilot training in AirAsia is continuous and very thorough. Rest assured that your captain is well prepared to ensure your plane will never get lost".
However, AirAsia insisted the article was written and published well before the disappearance of flight MH370.
An apology was issued for the article by AirAsia Executive Chairman Kamarudin Meranun. "It truly saddens me that this article was released at such an inopportune moment," he said.
It has been a year to forget for Malaysian airline companies, given the disappearance of MH370 in March and MH17 in July which was shot down over Ukraine near the Russian border.
The wreckage of Malaysia Airlines Flight 370 has not been found nine months on, as well as the 227 passengers on board.
Meanwhile, Malaysia Airlines Flight 17 was expected to touch down in Kuala Lumpur from Amsterdam, but was shot down over area controlled by pro-Russian separatists. All 283 passengers and 15 crew on board were killed.