JAKARTA, Indonesia – An AirAsia plane with 162 people on board lost contact with ground control on Sunday while flying over the Java Sea after taking off from a provincial city in Indonesia for Singapore. The two countries immediately launched a search and rescue operation, but there was no word on the plane’s whereabouts more than six hours after it went missing.

AirAsia, a regional low-cost carrier with presence in several Southeast Asian countries, said in a statement that the missing Airbus A320-200 was on the submitted flight plan route. However, it had requested deviation due to weather before communication with the aircraft was lost while it was still under the control of the Indonesian Air Traffic Control.

“We don’t dare to pressume what has happened except that it has lost contact,” Djoko Murjatmodjo, Indonesia’s acting director general of transportation, told reporters. He said the last contact between the pilot and air traffic control was at 6:13 a.m. “when he asked to hinder cloud by turning left and go higher to 34,000 feet.”

He said there was no distress signal from Flight QZ8501.

The contact was lost about 42 minutes after the single-aisle jetliner took off from Indonesia’s Surabaya airport, Hadi Mustofa, an official of the transportation ministry told Indonesia’s MetroTV. It was about an hour before it was scheduled to land in Singapore.

The plane had two pilots, five cabin crew and 155 passengers, including 16 children and one infant, AirAsia Indonesia said in a statement. Indonesian officials had earlier said there were 161 people on board, presumably because the infant was not counted.

The AirAsia statement said there were six foreigners – three South Koreans and one each from Singapore, Malaysia and France. The rest were Indonesians.

It said the captain in command had a total of 6,100 flying hours, a substantial number, and the first officer a total of 2,275 flying hours.

At Surabaya airport, dozens of relatives sat in a room, many of them talking on mobile phones and crying. Some looked dazed.

Murjatmodjo, the Indonesian official, said the plane is believed to have gone missing over the Java Sea between Tanjung Pandan on Belitung island and Pontianak, on Indonesia’s part of Kalimantan island.

He said the pilot contacted Jakarta air traffic control 6:12 a.m. reporting clouds and asking to go higher from 32,000 feet to 34,000 feet, the usual cruising altitude for jetliners.

The Singapore statement said search and rescue operations have been activated by the Indonesian authorities. It said the Singapore air force and the navy also were searching with two C-130 planes.

Flightradar24, a flight tracking website, said the plane was delivered in September 2008, which would make it six years old.

The Malaysia-based AirAsia, which has dominated cheap travel in the region for years, has never lost a plane before. AirAsia Malaysia owns 49 percent of the Indonesian subsidiary.

This is the third major air incident involving Malaysia 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 until this day with 239 people in one of the biggest aviation mysteries. 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 on July 17. A total of 298 people on board were killed.

The crew’s request for an unusual route is curious since the weather “didn’t seem to be anything unusual,” said William Waldock, an expert on air crash search and rescue with Embry-Riddle Aeronautical University in Prescott, Arizona.

Severe weather is the reason pilots usually request a different route, but in this case the “winds were light, there were a few thin clouds, but that’s about it,” he said in an interview.

Waldock cautioned against drawing comparisons to the disappearance of Malaysia 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.”

The circumstances bode well for finding the plane since the intended flight time was less than two hours and there is a known position at which the plane disappeared, he said.