The AirAsia jet carrying 162 passengers that disappeared over 24 hours ago is suspected to be on the bottom of the ocean floor, Indonesia's top rescue officials said at a press conference Monday.

"Based on the coordinates that we know, the evaluation would be that any estimated crash position is in the sea, and that the hypothesis is the plane is at the bottom of the sea," National Search and Rescue chief Henry Bambang Soelistyo told a news conference, according to the Associated Press.

First Admiral Sigit Setiayana, the Naval Aviation Center commander at the Surabaya air force base, told the Associated Press that 12 navy ships, five planes, three helicopters and a number of warships were talking part, along with ships and planes from Singapore and Malaysia. The Australian Air Force also sent a search plane.

Setiayana said visibility was good. "God willing, we can find it soon," he told The Associated Press.

Malaysia and Singapore each planned to deploy one C-130 plane and three ships. Australia will also help, he added.

More On This...

William Waldock, an expert on air crash search and rescue with Embry-Riddle Aeronautical University in Prescott, Arizona, cautioned against drawing comparisons to Flight 370.

The circumstances bode well for finding Flight 8501 since the intended flight time was less than two hours, and there is a known position where the plane disappeared, he told the Associated Press.

A groom-to-be, his parents and three brothers are believed to be among those aboard an Air Asia jet carrying 162 people that vanished over the Java Sea early Sunday amid stormy weather.

The fiancé of Alain Oktavianus Siaun told reporters that she was trying to stay positive after hearing the news that AirAsia Flight 8501 had disappeared en route to Singapore, the Star in Malaysia reported Sunday.

“I heard it on the radio and immediately browsed the Internet and saw the news,” Louise Sidharta said, according to told the newspaper.  “My heart knew by then that my fiancé was on that flight.”

Siaun was heading to Singapore to vacation with his family for the last time as a bachelor. Sidharta took a later flight from Surabaya to Singapore. She spoke to a horde of reporters at the Singapore Changi International Airport.

“We have to stay positive and hope that they (loved ones) could be found soon,” she said.

AirAsia said there are 155 passengers on board—138 adults, 16, children and one infant. Also on board are two pilots and five crew members.

The Associated Press said dozens of relatives of people aboard the plane gathered in a room at the Surabaya airport to await word about their loved ones.

Sky News said a British businessman and his two-year-old daughter are believed to be on the flight. Most on board are from Indonesia, with three from South Korea and one each from Singapore, Malaysia, France and the United Kingdom.

Indonesia and Singapore have launched a search and rescue operation after the flight was reported missing.

Flight 8501 was scheduled to make a relatively short early-morning flight from Surabaya, Indonesia to Singapore, but lost contact with Jakarta air traffic control at 6:24 a.m. local time (6:24 p.m. Eastern Time Saturday), approximately an hour before it was due to land.

Eleven minutes earlier, according to Djoko Murjatmodjo, Indonesia's acting director general of transportation, the pilot had "asked to hinder cloud by turning left and go higher to 34,000 feet." Murjatmodjo said that there was no distress signal from the plane. AirAsia Indonesia had earlier confirmed that the pilot had asked to change course due to bad weather in the area.

"We hope we can find the location of the plane as soon as possible, and we hope that God will give us guidance to find it," Murjatmodjo told reporters. "We don't dare to presume what has happened except that it has lost contact.”

Flight 8501 was last seen on radar at 6:16 a.m., and a minute later was no longer there, he added.

"This is my worst nightmare," AirAsia founder Tony Fernandes said in a tweet. Earlier, Fernandes, the face of the company and an active Twitter user, sent out a tweet that said: "Thank you for all your thoughts and prays[sic]. We must stay strong."

Sunardi, a weather forecaster at the Indonesia's Meteorology and Geophysics Agency who uses only one name, told the Associated Press that dense storm clouds were detected up to 44,000 feet in the same area at the time the plane was reported to have lost contact.

"There could have been turbulence, lightning and vertical as well as horizontal strong winds within such clouds," he said.

AirAsia said the single-aisle Airbus A320-200 had an Indonesian captain and a French co-pilot. The airline's statement added that the plane's captain had a total of 6,100 flying hours, while the first officer had flown 2,275 hours.

Flightradar24, a flight tracking website, said the plane was delivered in September 2008, which would make it six years old. It said the plane was flying at 32,000 feet, the regular cruising altitude for most jetliners, when the signal from the plane was lost. AirAsia said that the plane had undergone its last scheduled maintenance on Nov. 16.

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

Transport Minister Ignasius Jonan told reporters in Surabaya that the position was believed to be near the coast line. He said search and rescue efforts now involved the Indonesian army, the national Search and Rescue Agency as well as Singapore and Malaysia. The Search and Rescue Agency's operation chief, Maj. Gen. Tatang Zaenudin, said 200 rescuers had been deployed to the east side of Belitung island.

Air Force spokesman Hadi Tjahjanto said three aircraft, including a surveillance plane, had been dispatched to the area. The Singapore air force and the navy also were searching with two C-130 planes.

The Singapore aviation authority said it was informed about the missing plane by Jakarta ground control about half an hour after the contact was lost.

Malaysian Prime Minister Najib Razak, expressed solidarity with AirAsia. In a tweet he said: "Very sad to hear that AirAsia Indonesia QZ8501 is missing. My thoughts are with the families. Malaysia stands ready to help."

White House spokesman Eric Schultz said in a statement that President Obama had briefed about the missing flight and officials would continue to monitor the situation.

According to the website, Flight QZ8501 was scheduled to depart from Juanda International Airport, near Surabaya on the Indonesian island of East Java at 5:30 a.m. local time, with arrival in Singapore scheduled for 8:20 a.m. Singapore time (7:20 p.m. Eastern Time Saturday). It had last flown the route on Dec. 26.

The Airbus A320 is a workhorse of modern aviation. Similar to the Boeing 737, it is used to connect cities anywhere from one to five hours apart. There are currently 3,606 A320s in operation worldwide, according to Airbus. The A320 family of jets, which includes A319 and A321, has a very good safety record, with just 0.14 fatal accidents per million takeoffs, according to a safety study published by Boeing in August.

AirAsia, which has a presence in several Southeast Asian countries, has never lost a plane before. AirAsia Malaysia owns 49 percent of the Indonesian subsidiary. The airline typically flies short routes of just a few hours, connecting large cities of Southeast Asia. However, recently it has tried to expand into long-distance flying through its sister airline AirAsia X.

Earlier this year, national carrier Malaysia Airlines lost two planes. Flight MH370 vanished on March 8 with 239 passengers and crew on board. On July 17, Flight MH17 was shot down over Ukraine, killing all 298 people on board.

William Waldock, an expert on air crash search and rescue with Embry-Riddle Aeronautical University in Prescott, Arizona, cautioned against drawing comparisons to the disappearance of Malaysia Airlines 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.

The Associated Press contributed to this report.