Relatives of passengers on AirAsia flight QZ8501 began crying hysterically and fainting overnight as Indonesian television footage showed a body floating in the sea during aerial searches for the plane.

At least two distraught family members were carried out on stretchers from the room where they had been waiting for news in Surabaya, Indonesia's second largest city - the take-off point for the aircraft that disappeared during a storm on Sunday.

"My heart will be totally crushed if it's true. I will lose a son," 60-year-old Dwijanto, who like many Indonesians goes by one name, said.

More than 48 hours after the Airbus A320-200 lost contact carrying 162 people to Singapore, aerial searchers spotted items in the Java Sea which officials said were from the plane.

An Indonesian search helicopter and pieces of debris apparently belonging to the AirAsia flight. (AFP) (AFP)

As the first body was shown floating in the water on rolling television news, relatives burst into tears and hugged one another amid cries for more ambulances, said an AFP reporter at the scene.

One man covered his face and had to be held up by two other men before he fainted and was taken out by stretcher. Another woman was screaming and crying as she was supported by the mayor of Surabaya.

A female AirAsia officer shouted at the television media for showing footage of a floating body, while about 200 journalists were barred from the room holding the families, the windows of which were boarded up.

"Is it possible for you not to show a picture of the dead? Please do not show a picture of a dead body," said the officer. "That's crazy."

A crew of an Indonesian Air Force C-130 airplane of the 31st Air Squadron scans the horizon for the missing jet. (AAP) (AAP)

Debris found by searchers in the hunt for the missing AirAsia flight. (AFP) (AFP)

Indonesia's National Search and Rescue Agency chief has confirmed that just three bodies have been recovered so far in the search for the AirAsia plane which crashed in the Java Sea, after another official said 40 had been found.

The fuselage and wreckage of the aeroplane has also been located, after searchers earlier discovered its shadow in the water.

"Today we evacuated three bodies and they are now in the warship Bung Tomo," Bambang Soelistyo told a news conference in Jakarta, adding that they were two women and a man.

Navy spokesman Manahan Simorangkir told AFP earlier that, according to naval radio, a warship had recovered more than 40 bodies from the sea. But he later said that report was a miscommunication by his staff.

Relatives of the 162 people missing on the plane hugged each other and burst into tears in Surabaya, as they watched footage showing a body floating in the sea on a television feed of a press conference revealing red, while and black debris had been found in the search for the missing jet.

Debris found by searchers in the hunt for the missing AirAsia flight. (AFP)

Debris found by searchers in the hunt for the missing AirAsia flight. (AFP)

Indonesia's National Search and Rescue Agency chief Bambang Soelistyo said an air force C-130 Hercules spotted a "shadow" in the form of a plane on the seabed, believed to be the missing jet.

Meanwhile in Thailand, another AirAsia plane was forced to turn back to Bangkok after an "irregularity" was detected on board, while a AirAsia Zest Airbus overshot a runway in the Philippines during a landing, forcing nearly 160 passengers and crew to evacuate via emergency slides.

Indonesia's director general of civil aviation said debris spotted during an aerial search for the AirAsia flight was from the missing plane.

"For the time being it can be confirmed that it's the AirAsia plane and the transport minister will depart soon to Pangkalan Bun," Djoko Murjatmodjo said.

"Based on the observation by search and rescue personnel, significant things have been found such as a passenger door and cargo door. It's in the sea, 100 miles (160 kilometres) southwest of Pangkalan Bun," he said, referring to the town in Central Kalimantan, on the island of Borneo.

Indonesian Air Force members look out the cockpit windows of C-130 for the missing AirAsia jet. (AAP) (AAP)

An Indonesian Navy helicopter assists in the search for missing AirAsia flight QZ8501 near Batam, south of Singapore. (AP) (AP)

Video images from Reuters also appeared to show a body, which officials pulled out of the water.

An AFP photographer on the same flight that spotted the debris said he had seen objects in the sea resembling a life raft, life jackets and long orange tubes.

Fifty air and sea vehicles were looking for missing AirAsia flight 8501 in a 156,000 km search area after the plane went missing in bad weather in the Java Sea with 162 people on board.

An oil patch spotted off Belitung island was earlier thought to provide an indication to narrow the search field, however it later emerged it was a coral reef.

Indonesian navy helicopters saw smoke near the island, but CNN reports authorities don't know whether there's any connection to the missing jet.

It was earlier reported that wreckage had been spotted in the ocean, about 1100km from where the plane disappeared.

However, experts believed those objects were too far from the jet's last known location, and rubbish was often found in the area as it was a busy shipping lane.

Basarnas search agency chief Bambang Sulistyo made the devastating announcement yesterday the plane was likely at "the bottom of the sea".

Australia has added an extra plane in its contribution to the search as reports emerge that a Melbourne university student was on the flight.

Kevin Alexander Soetjipto was travelling from Indonesia to Singapore with relatives when the plane lost contact with air traffic control.

Two RAAF P3 Orion planes with specialist search equipment are now part of the international search.

Foreign Minister Julie Bishop wouldn't be drawn on earlier reports of debris.

"I'm sure there will be sightings of all sorts of debris in the ocean, but we will wait until there's actual confirmation of the plane sighting before we make any official comment on that," she said in Adelaide today.

Meanwhile, somebody "dropped the ball" when making the flight plan for missing AirAsia flight QZ8501, aviation expert Neil Hansford says.

Mr Hansford told the TODAY Show human factors were undoubtedly a factor in the jet's disappearance.

"I've said all along it was never going to be engineering," he said.

One of the pilots was reportedly denied a request to increase altitude to avoid storm clouds just six minutes before the jet disappeared.

The pilot asked permission to turn left and climb from 32,000ft to 38,000ft due to the bad weather but air-traffic controllers in Indonesia said another plane was already in the airspace.

Mr Hansford said veteran pilots called the area where the plane vanished, over the Java sea, the "thunderstorm factory".

He said most flights went around the area, not through it.

Most modern aircraft (and all Airbus aircraft) are equipped with one or more Emergency Locator Transmitters (ELTs) to aid recovery teams in the search for survivors or wreckage.

When an incident has occurred, such as a collision into terrain or water, the ELT is designed to automatically activate and transmit a distress signal to a network of orbiting satellites.

The location of the beacon can then be determined by the transmitted GPS coordinates or by measuring the Doppler shift, thereby increasing the chances of survivors or wreckage being found by search parties.

Aircraft are normally equipped with more than one ELT; generally a ‘fixed’ automatic model is mounted within the aircraft fuselage, with one or more portable models available to the crew inside the cabin, and typically activated after evacuation.

While no firm conclusions can be made regarding QZ5801 at this time, the lack of an ELT signal from the aircraft has led to speculation surrounding its fate.

The transmissions sent by the ELT equipment require a direct line of sight to the orbiting constellation of satellites, and this line of sight is easily disrupted by water or other objects.

If the aircraft had begun sinking on impact, the ELT equipment may have already been submerged and unable to transmit its location to the satellite constellation.

It is also possible that the ELT equipment was damaged on impact.

Experts have previously estimated that fixed ELT equipment is only successful in a quarter of all accidents, with the failure to trigger manual transmissions from portable ELT units contributing to this figure.

If not already underway, the search parties in the Java Sea will soon concentrate on underwater recovery efforts, starting with a search for the Cockpit Voice Recorder (CVR) and Flight Data Recorder (FDR), colloquially referred to together as the ‘black box’.

The CVR and FDR are designed to withstand extreme conditions; up to 3400G for 6.5 milliseconds (to survive the initial impact), temperatures of up to 1100°C for an hour (to survive any post-crash fires) and depths of up to 6000 metres for 30 days.

To assist in the search for the recorder modules, each is also fitted with an Underwater Locator Beacon (ULB).

This beacon is automatically activated upon becoming submerged in water, repeatedly transmitting an acoustic ‘ping’ which can be heard using special equipment.

The ULB is mandated to operate for a minimum of 30 days, providing search parties with a window of opportunity to listen for the distinctive pings during the recovery operation.

Sonar equipment is also expected to be deployed in conjunction with the ULB locator, which will allow search parties to analyse the seabed for debris.

The retrieval of the cockpit and data recorders will be crucial in answering questions surrounding the events that led to the disappearance of QZ5801.

If found intact, the CVR will hold up to two hours of cockpit audio, while the FDR will hold up to 25 hours of technical data from aircraft systems, providing air crash investigators with an accurate picture of events leading up to (and during) the aircraft’s disappearance.

The loss of Flight QZ5801 has been compared to that of Air France Flight 447, as well as Malaysian Airlines Flight MH370.

Air France Flight 447 was lost over the Atlantic Ocean after an instrument malfunction resulted in crew disorientation, sending the Airbus A330 into an aerodynamic stall.

After being unable to locate the underwater beacon, authorities later recovered the voice and data recorders after an intensive two-year search.

Investigations into the disappearance of Malaysian Airlines Flight MH370 have so far failed to recover any debris from the missing jet, despite an exhaustive search lead by Australian recovery teams.