The search for a missing Malaysia Airlines passenger jet expanded Tuesday, as relatives of the 239 people on board prepared to deal with expected bad news.
There has been no trace of the Boeing 777 since it disappeared from radar without any distress calls Saturday, about an hour after leaving Kuala Lumpur.
Dozens of ships and planes involved in the search have failed to turn up any leads, following earlier reports that possible debris or spilled oil was located.
The search has expanded well beyond the plane's scheduled flight path. It now spans 185 kilometers from where the jet disappeared, including areas on land.
Malaysian officials are exploring a wide range of scenarios that may have brought down the Beijing-bound jet, including an explosion, hijackers, pilot error or mechanical failure.
Jim Tilmon is an aviation expert and former commercial airlines and military pilot. He tells VOA's Daybreak Asia that locating debris will be key to explaining the cause of any crash.
"If the airplane broke up at that altitude, or anything close to that altitude, it would spread debris over a very wide area...On the other hand, if we have a relatively confined debris field, it may lend one to understand that this airplane was in pretty good shape in terms of being whole as it went into the water."
Officials are also investigating two passengers who boarded the aircraft with stolen Italian and Austrian passports. Malaysian police said Tuesday one of the men was a 19-year-old Iranian national who was likely trying to migrate to Germany. He is not thought to have terror links.
The identity of the other man is under investigation, though officials have said stressed the men's presence on the flight may have been merely a coincidence.
The speculation has done little to comfort those waiting for information about their relatives. Ms. Wang, whose mother is on the plane, said Tuesday she is still hopeful.
"As a family member who lost contact with their families, the most concerned issue is to find out their own family members, find out where they are and find out the result. If there is no progress on search and rescue effort, we hope to increase efforts on investigating the possibility of hijacking."
About two-thirds of the people on board were Chinese nationals, with the remainder from other Asian countries, Europe and North America.
At airports in the region, many travellers remain nervous. Hoo Wee Sin was waiting to board a plane at the Kuala Lumpur International Airport where flight MH307 took off.
"Frankly speaking, I feel worried about (flying). I feel troubled, too, because it only happened about three or four days ago, so it's not that peaceful actually."
The Boeing 777 is a very popular plane with an excellent safety record. The most recent accident involving a Boeing 777 was the Asiana Airlines crash at San Francisco International Airport in July 2013. Three people were killed. Pilot error is suspected in that incident.