Flight QZ8501, which had 162 people on board, lost contact with air traffic control at 7:24 a.m. Sunday local time near Belitung Island, Indonesia, according to a statement from AirAsia. It was scheduled to land in Singapore at 8:30 a.m. local time.
The plane was several hours past the time when its fuel would have been exhausted, Indonesian officials said during a news conference Sunday.
Sixteen children and one infant were among the passengers.
This was the third air incident this year for Malaysia, which lost two Malaysia Airlines jumbo jets, one that disappeared without a trace over the South China Sea and another that was shot down over Ukraine.
The six-year-old aircraft was on its submitted flight plan but the pilot requested a deviation because of en-route weather before communication with the aircraft was lost, AirAsia said. The plane was under the control of the Indonesian Air Traffic Control and had been in the air for about 42 minutes when contact was lost.
The Indonesia air transportation director said the pilot requested to increase altitude to 38,000 feet from 32,000 feet to "avoid clouds." Thunderstorms were reported in the area with clouds up to 50,000 feet, Indonesian officials said.
The jet was flying at the regular cruising altitude for most jetliners — 32,000 feet — when the signal was lost, according to flight tracking website Flightradar24. No distress reports came from the plane, officials 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," AirAsia said.
The captain in command had a total of 6,100 flying hours and the first officer had a total of 2,275 flying hours, according to the airline. The aircraft had undergone its last scheduled maintenance on November 16, 2014.
The flight manifest for the jet showed there were 155 passengers on board plus seven crew members.
Of the passengers, 156 were Indonesians, three were South Korean, and there was one traveler each from Malaysia and Singapore and France, according to AirAsia.
The Civil Aviation Authority of Singapore said it was informed about the missing plane by Jakarta ground control about half an hour after contact was lost.
The Singapore air force and the navy were activated with two C-130 ready to assist Indonesia authorities in the search, according to the aviation authority.
"We remain ready to provide any assistance to support the search and rescue effort," the CAAS said.
A waiting area was set up at Changi Airport in Singapore, where the plane had been scheduled to land, with facilities and support for relatives and friends of the passengers on the plane. At Juanda International Airport in Surabaya, dozens of relatives sat in a room, many of them talking on mobile phones and crying. Some looked dazed, the Associated Press reported.
The White House said President Obama was briefed on the flight.
This caps a terrible year for Malaysia and air travel.
AirAsia is Malaysian-based, and in March, Malaysia Airlines flight 370, a wide-bodied Boeing 777 with 239 people on board, vanished soon after taking off from Kuala Lumpur for Beijing. It hasn't been found.
In July, another Malaysia Airlines Boeing 777 was shot down over Ukraine, killing all 298 on board.