Flight 8501 was bound for Singapore from Surabaya, Indonesia, when it lost contact with air traffic control at about 7:24 a.m. (6:24 p.m. ET on Saturday), the airline said in a statement. The time in Surabaya is 12 hours ahead of Eastern Standard Time; Singapore is 13 hours ahead of ET.
Indonesia called off the daylong air search for the night at about 7 a.m. ET. Achmad Toha, an official with the country's search and rescue agency, said some search ships were still in the area. The air search was set to resume at dawn Monday.
"We have no idea at the moment what went wrong," said Tony Fernandes, a Malaysian businessman and CEO of the regional low-cost carrier. "Let's not speculate at the moment."
Djoko Murjatmodjo, Indonesia's acting director general of transportation, said that minutes before the plane disappeared from radar, the pilot asked air traffic control for permission to avoid a cloud bank by turning left and going higher, to 34,000 feet. Flight 8501 gave no distress signal, he said.
AccuWeather meteorologist Tyler Roys told USA TODAY the area along the flight path at that time was blasted by a string of severe thunderstorms.
"It's hard to say if 34,000 feet would have been enough," Roys said. "We know the thunderstorms were very tall, very high up. They could have encountered severe turbulence, strong wind shear, lightning and even icing at that altitude."
AirAsia said in a statement that the plane has six Indonesian crew, a French crew member and 155 passengers, including 16 children and one infant. Among the passengers are three South Koreans, a Singaporean, a Malaysian and a Briton. The rest are Indonesians, the statement said.
Murjatmodjo said the plane is believed to have gone missing somewhere over the Java Sea between Tanjung Pandan on Belitung Island and Pontianak, on Indonesia's part of Borneo island. Contact was lost about 42 minutes after takeoff from Surabaya airport, authorities said.
At Surabaya's Juanda International Airport, dozens of relatives sat in a room, many talking on mobile phones, crying and looking dazed as the hours dragged on without additional news. As word spread, more and more family members arrived at the crisis center to await word.
Singapore's prime minister, Lee Hsien Loong, tweeted his condolences: "Saddened to hear of missing flight #QZ8501. My thoughts are with the passengers and their families."
In Washington, White House spokesman Eric Schultz said President Obama had been briefed on the lost plane and that "White House officials will continue to monitor the situation."
AirAsia, which has dominated cheap travel in the region for years, has never lost a plane. Before AirAsia released its statement about the missing plane, officials changed the airline's Facebook and Twitter account logos from red to gray.
The plane's captain, identified in flight documents as Capt. Iriyanto, had a total of 6,100 flying hours. The first officer had a total of 2,275 flying hours, said AirAsia, based in Sepang, Malaysia, near Kuala Lumpur.
Flightradar24, a flight tracking website, said the Airbus A320-200 was delivered in September 2008. The plane, with registration number PK-AXC, had its last scheduled maintenance Nov. 16, airline officials said.
Worldwide, 3,606 A320s are in operation, according to Airbus. In a statement, the firm said the AirAsia aircraft had accumulated approximately 23,000 flight hours in 13,600 flights. It said it will provide full assistance to BEA, the French safety investigation authority, and to the authorities in charge of the investigation.
"The thoughts of the Airbus management and staff are with all those affected by Flight QZ 8501," the statement added.
This is the third major air incident for Southeast Asia this year:
• On March 8, Malaysia Airlines Flight 370, a wide-bodied Boeing 777, went missing soon after taking off from Kuala Lumpur for Beijing. It remains missing with 239 people in one of the biggest aviation mysteries.
• On July 17, another Malaysia Airlines flight, also a Boeing 777, was shot down over rebel-controlled eastern Ukraine while on a flight from Amsterdam to Kuala Lumpur. A total of 298 people on board were killed.
Malaysia Airlines offered its support to AirAsia, tweeting: "#staystrong @AirAsia - Our thoughts and prayers are with all family and friends of those on board QZ8501."
Malaysian prime minister Najib Razak tweeted: "Very sad to hear that AirAsia Indonesia QZ8501 is missing. My thoughts are with the families. Malaysia stands ready to help."
William Waldock, an expert on air crash search and rescue with Embry-Riddle Aeronautical University in Prescott, Ariz., cautioned against drawing comparisons to the disappearance of Flight 370.
"I think we have to let this play out," he said. "Hopefully, the airplane will get found, and if that happens it will probably be in the next few hours. Until then, we have to reserve judgment."
