(CNN) -- An oil slick, the sound of a distant "ping," objects in the water, and now this: smoke spotted rising from an island in the Java Sea. 
 
 As ships, planes and helicopters scour the waters off Indonesia's coast for missing AirAsia Flight QZ8501, there have been several reports of possible signs of the missing plane. 
 
 So far, officials say, none of them have panned out. 
 
 On Tuesday, search teams will be checking the area where Indonesian navy helicopter crews saw the smoke, the head of search and rescue in the province of Bangka-Belitung told CNN Indonesia. But authorities don't know whether there's any connection to the missing jet. 
 
 Local media in Indonesia reported the smoke was seen on Long Island, one of thousands that make up the archipelago that forms Indonesia. 
 
 Searchers have been scanning the water's surface for signs of the plane, which went missing with 162 people aboard on Sunday as it flew between the islands of Belitung and Borneo, a heavily traveled shipping channel with shallow waters. 
 
 "Our early conjecture is that the plane is in the bottom of the sea," said Bambang Sulistyo, the head of Indonesia's search-and-rescue agency. That belief is based on the plane's flight track and last known coordinates, he said. 
 
 Several possible signs of the missing plane, including an oil slick within the search zone and the sound of a faint "ping," have been discounted, according to Indonesian authorities, who are heading the search. 
 
 Indonesia Vice President Jusuf Kalla said there were "some reports from Australia" about possible objects found, but it was unclear whether they were from the plane. 
 
 Because there is a great deal of traffic along the water in the search area, authorities have cautioned that objects found might have nothing to do with the missing aircraft. 
 
 Rescuers say weather was probably a factor in the plane's disappearance, and it has made finding traces of the plane more difficult. 
 
 Large waves and clouds hampered the search for the plane on Sunday and Monday. 
 
 "It is not easy, of course ... the operation in the sea, especially in the bad weather like this," Kalla said. 
 
 But Kalla said his country will not give up or set a time limit for the operation. 
 
 The search area is expanding, with six zones added to the operation on Tuesday, Sulistyo told reporters. 
 
 Now, he said, teams in the air, on sea and on land are searching 13 zones over an area that stretches about 156,000 square kilometers (60,200 square miles). 
 
 What role did weather play? 
 
 Report: Higher altitude request denied 
 
 AirAsia says air traffic controllers lost contact with the aircraft at 7:24 a.m. Sunday, Singapore time (6:24 a.m. in Indonesia). 
 
 The plane, flying from the Indonesian city of Surabaya to Singapore, went missing as it flew over the Java Sea between the islands of Belitung and Borneo -- a heavily traveled shipping channel with shallow waters -- Indonesian authorities said. 
 
 Before the plane, an Airbus A320-200, lost contact with air traffic controllers, one of the pilots asked to change course and fly at a higher altitude because of bad weather, officials said. Heavy thunderstorms were reported in the area at the time. 
 
 Air traffic control approved the pilot's request to turn left but denied permission for the plane to climb to 38,000 feet from 32,000 feet, Djoko Murjatmodjo, an aviation official at the Indonesian Transport Ministry, told the national newspaper Kompas. 
 
 The increased altitude request was denied because there was another plane flying at that height, he said. 
 
 Djoko suggested that Flight 8501 ascended despite air traffic control denying it permission. 
 
 AirAsia CEO Tony Fernandes said storm clouds caused the pilot to ask for a flight plan change. But he added, "We don't want to speculate whether weather was a factor. We really don't know." 
 
 Once the aircraft is found, there will be a proper investigation, Fernandes said. 
 
 AirAsia CEO takes to Twitter 
 
 Relatives to be flown over search area 
 
 Amid the anxious wait, family members of the passengers have attended closed-door briefings with airport and airline officials at the airport in Surabaya. 
 
 Oei Endang Sulsilowati and her daughter were looking for information about her brother, his wife and their two children. 
 
 "We don't know what to do," Sulsilowati said. "We are just waiting for news." 
 
 A specially chartered plane will fly relatives of passengers over the search area Wednesday, AirAsia Indonesia CEO Sunu Widjatmoko told reporters in Surabaya on Tuesday. 
 
 The chartered Airbus A320 that will take families from Surabaya over the zone has room for as many as 180 people, he said. 
 
 Some police said authorities were seeking additional materials to help identify passengers, such as photos with close-ups of teeth, DNA, or fingerprints. But police officials later told CNN they were not immediately seeking these materials. 
 
 East Java Police have set up a disaster victims identification area at the Surabaya airport. 
 
 Of the people on board the passenger jet, 155 are Indonesian, three are South Korean, one is British, one is French, one is Malaysian and one is Singaporean, the airline said. 
 
 Eighteen children, including one infant, are among the passengers, the carrier said. Seven of the people on board are crew members. 
 
 Families of AirAsia flight passengers given support through the 'nightmare' 
 
 International search team 
 
 Since the flight disappeared in Indonesian airspace, Indonesia is heading up search efforts. 
 
 More than 1,100 search and rescue personnel from Australia, Singapore, Malaysia, South Korea, Japan and New Zealand are joining the search alongside Indonesia's teams, CNN Indonesia reported. 
 
 The missing plane is made by Airbus, a French company. And France has dispatched two investigators to Indonesia. They are due to arrive in Jakarta on Monday, France's Foreign Ministry said. 
 
 Malaysia's transportation minister said his country has deployed three vessels and three aircraft to assist in the search. And the Royal Australian Air Force said Monday that it was deploying a patrol plane to help. 
 
 The USS Sampson is on its way to the Java Sea to assist in the search for the missing AirAsia plane, a senior U.S. military official told CNN Chief National Security Correspondent Jim Sciutto. The Sampson, a guided-missile destroyer based in San Diego, deployed in October to take part in "maritime security exercises and training" in the Pacific. 
 
 China will dispatch aircraft and ships to participate in search and rescue efforts, the Chinese Ministry of National Defense said Tuesday. 
 
 The MH370 mystery 
 
 AirAsia, a successful budget airline group headquartered in Malaysia, had a clean safety record until the disappearance of Flight 8501. The missing plane is operated by the company's Indonesian affiliate. 
 
 The loss of contact with the plane comes nearly 10 months after the disappearance of Malaysia Airlines Flight 370, which dropped off radar over Southeast Asia on March 8 with 239 people on board. 
 
 AirAsia and MH370 cases are very different 
 
 Searchers have yet to find any remains of Flight 370, which officials believe went down in the southern Indian Ocean after mysteriously flying thousands of kilometers away from its planned route from Kuala Lumpur to Beijing. 
 
 But some aviation experts don't think the search for Flight 8501 will be as challenging as the hunt for MH370. 
 
 "We are not talking about the deep Indian Ocean here," CNN aviation correspondent Richard Quest said. "We are talking about congested airspace around Southeast Asia. There will be much better radar coverage. There's certainly better air traffic control coverage." 
 
 CNN's Susanna Capelouto, Andrew Stevens, Paula Hancocks and Lucia Isman contributed to this report. Azieza Uhnavy also contributed to this report. ||||| SURABAYA, Indonesia -- The search has resumed for the missing AirAsia Flight 8501 plane that is believed to have crashed into Indonesia's Java Sea, Sunday morning. Searchers continued looking for the aircraft Tuesday, with the search area widened in hopes of finding the airliner and its 162 passengers. 
 
 On Tuesday, an Indonesia National Search and Rescue spokesman said several pieces of debris had been spotted floating in the sea off Borneo island that might be linked to the missing jetliner. Yusuf Latif said an Indonesian military aircraft saw white, red and black objects, including what appeared to be a life jacket, off the coast, about 105 miles south of Pangkalan Bun. The agency dispatched at least one helicopter to pick up the items and take them to the search and rescue coordination post on Belitung Island. 
 
 The Reuters news agency says Indonesian television showed footage Tuesday of objects floating in the Java Sea that an official said could be part of the AirAsia jet. Indonesian TV showed two relatively large objects, one orange and one grey or brown, floating on the surface. The largest appeared to be several yards long. 
 
 Also, Dr. Max Ruland, Director of Operations for the search and rescue mission, confirmed to CBS News that two Cessna jets have been dispatched to check on reports of smoke on an island in the search zone, which is larger than the state of California. 
 
 The debris and smoke reports are the latest lead in an a multinational search effort for the missing plane concentrated over the Java Sea. 
 
 Indonesia's search and rescue agency said in a press conference that emergency signals detected earlier were not from Flight 8501. 
 
 Based on the plane's last known coordinates, the aircraft probably crashed into the water and "is at the bottom of the sea," Indonesia search-and-rescue chief Henry Bambang Soelistyo said. Still, searchers planned to expand their efforts onto land on Tuesday. 
 
 REUTERS / Darren Whiteside 
 
 The plane, en route to Singapore, disappeared from radar less than an hour into the flight. Officials are looking at many factors that contributed to the disappearance including technical failures and weather. 
 
 Djoko Murjatmodjo, said the last communication between the pilot and air traffic control was at 6:13 a.m. when the pilot "asked to avoid clouds by turning left and going higher to 34,000 feet." It was last seen on radar at 6:16 a.m., and a minute later was no longer there, he said. 
 
 Meanwhile, the United States has agreed to join in the search for the missing airliner. The the USS Sampson is being sent to aid in the search for wreckage, CBS News has learned. It is expected to arrive during evening hours and miss the beginning of the third day of the search. 
 
 Searchers spotted two oily patches and floating objects in separate locations, but no one knew whether any of it was related to the plane that vanished Sunday halfway into what should have been a two-hour hop from Surabaya, Indonesia, to Singapore. Officials saw little reason to believe the flight met anything but a grim fate. 
 
 When planning a route prior to takeoff, pilots try to avoid thunderstorms. But if one pops up during the trip, or crews encounter rough turbulence, they routinely ask to fly around storms or move below or above the turbulence. 
 
 A storm alone isn't going to bring down a modern plane designed to withstand severe weather. But weather paired with a pilot error or a mechanical failure could be disastrous. It's like a car driving on a highway during a thunderstorm. 
 
 Plenty of vehicles get through bad weather safely but one that gets a flat tire or takes a turn too fast might crash. Pilots rely on sophisticated weather-radar systems that include a dashboard display of storms and clouds, as well as reports from other crews, to steer around dangerous weather. 
 
 "Typically we don't see large commercial aircrafts being taken down by severe weather...when you talk about smaller aircrafts going into thunderstorms, in-flight break ups are a possibility," former Chairman of the NTSB and is now President and CEO of the National Safety Council Deborah Hersman said Monday on "CBS This Morning." 
 
 Jakarta's air force base commander, Rear Marshal Dwi Putranto, said an Australian Orion aircraft had detected "suspicious" objects near an island about 100 miles (160 kilometers) off central Kalimantan. That's about 700 miles from where the plane lost contact, but within Monday's greatly expanded search area. 
 
 "However, we cannot be sure whether it is part of the missing AirAsia plane," Putranto said. "We are now moving in that direction."Air Force spokesman Rear Marshal Hadi Tjahnanto told MetroTV that an Indonesian helicopter spotted two oil patches in the Java Sea east of Belitung island, much closer to where the plane lost contact. He said oil samples would be collected and analyzed. 
 
 It's the second flight to go missing over Southeast Asian waters this year. This time, many are wondering why there hasn't been evidence that the pilots sent a distress signal. 
 
 "So far the information that we've heard from the authorities on the ground, is that they asked for clearance to a higher altitude. There wasn't any distress signal that was sent that's been reported at this point," Hersman said. "But I will tell you for pilots, they have responsibilities and they are aviate, navigate and communicate, and communication in an emergency is really the last thing they're focusing on. They've got to handle that airplane and make sure that that is their first priority." 
 
 ROYAL MALAYSIAN NAVY 
 
 Nearly all the passengers and crew are Indonesians, who are frequent visitors to Singapore, particularly on holidays. 
 
 Ruth Natalia Puspitasari, who would have turned 26 on Monday, was among them. Her father, Suyanto, sat with his wife, who was puffy-eyed and coughing, near the family crisis center at Surabaya's airport. 
 
 Suyanto remembers the concern his daughter showed for the families of the Flight 370 tragedy. Puspitasari once told him how sad it must be for the victims' relatives who were left waiting for their loved ones with no certainty. 
 
 "I don't want to experience the same thing with what was happened with Malaysia Airlines," he said as his wife wept. "It could be a long suffering." 
 
 Few believe this search will be as perplexing as the ongoing one for Flight 370, where what happened onboard remains a total mystery. Authorities suspect the plane was deliberately diverted by someone on board and ultimately lost in a remote area of the Indian Ocean with notoriously deep water. Flight 8501 vanished over a heavily traveled sea that is relatively shallow, with no sign of foul play. 
 
 The captain, Iryanto, who like many Indonesians uses a single name, had more than 20,000 flying hours, AirAsia said. 
 
 "Papa, come home, I still need you," Angela Anggi Ranastianis, the captain's 22-year-old daughter, pleaded late Sunday in social-media comments that were widely quoted in the Indonesian press. 
 
 People who knew Iryanto recalled that he was an experienced military pilot, flying F-16 fighters before shifting to commercial aviation. His French co-pilot, Remi Plesel, had been in Indonesia three years and loved to fly, his sister, Renee, told France's RTL radio. 
 
 "He told me that things were going well, that he'd had a good Christmas. He was happy. The rains were starting," she said. "The weather was bad." 
 
 The suspected crash caps an astonishingly tragic year for air travel in Southeast Asia, and Malaysia in particular. Malaysia-based AirAsia's loss comes on top of the still-unexplained disappearance of Malaysia Airlines Flight 370 in March with 239 people aboard, and the downing of Malaysia Airlines Flight 17 in July over Ukraine, which killed all 298 passengers and crew. 
 
 "Until today, we have never lost a life," AirAsia group CEO Tony Fernandes told reporters. "But I think that any airline CEO who says he can guarantee that his airline is 100 percent safe is not accurate."
– The disappearance of another jet in Southeast Asia while the fate of Malaysia Airlines Flight 370 remains a mystery comes as a shock to the aviation world, but experts stress that the two cases are very different. The New York Times runs through some of the differences with AirAsia Flight 8501: Unlike with Flight 370, there has been no sign that anybody on Flight 8501 intentionally disabled any onboard systems, meaning that investigators should have the normal automatic transmissions from the flight to help the search. Flight 370 disappeared on a clear night, while Flight 8501 was believed to have encountered stormy weather, with weather agencies having reported lightning strikes along its route. The AirAsia pilot's last communication with air traffic control was a request "to avoid clouds by turning left and going higher to 38,000 feet." Flight 370's pilot was very experienced, with more than 18,000 hours of flying time, while the combined experience of Flight 8501's pilot and co-pilot is believed to be less than half that. Neither Flight 370 nor Flight 8501 issued an emergency distress call, but, as the AP notes, "pilots are trained to focus first on the emergency at hand and then communicate only when free," and there's no sign that the AirAsia flight diverted sharply from its intended course the way the Malaysia Airlines flight did. Another major difference is the search area for Flight 8501, which is much smaller and shallower than the vast area that has been searched for Flight 370. "We are not talking about the deep Indian Ocean here," says CNN aviation correspondent Richard Quest. "We are talking about congested airspace around Southeast Asia. There will be much better radar coverage. There's certainly better air traffic control coverage."