False alarms, swirling rumours and contradictory statements have made the wait all the more agonising for the families of the 239 people on board the missing Malaysia Airlines flight MH370.
As the search dragged into its fifth day, here are some of the key areas of confusion:
Did the plane veer off course?
Malaysia's air force chief on Sunday raised the possibility that the plane inexplicably turned back after taking off from Kuala Lumpur en route to Beijing a day earlier.
RMAF's Tan Sri General Rodzali Daud said the theory was "corroborated by civil radar", without giving further details.
Late Tuesday, Rodzali was quoted by a local Bahasa Malaysia daily as saying the aircraft had been tracked hundreds of miles from its intended flight path, over the Strait of Malacca.
Vietnam had initially said the plane was approaching its airspace when it vanished from radar screens.
Rodzali has since insisted that he did not make the comments attributed to him by the Berita Harian newspaper, and the report was "inaccurate and incorrect".
The search today swung even further up Malaysia's west coast, towards the Andaman Sea, but officials gave no indication there was a firm reason to expand the search other than its failure to bear fruit so far.
Officials say contact with the aircraft was lost at around 1.30am Malaysian time, about an hour after take-off from Kuala Lumpur International Airport.
Initially, Malaysia Airlines had put the last contact time at 2.40am.
The timing of 1.30 am would place the plane between Malaysia and Vietnam, where Vietnamese air traffic control and flight-tracking websites say the plane vanished off radar.
The later time of 2.40 am could suggest the plane had indeed veered radically off-course.
Despite the Malaysian air force chief's denial of the Berita Harian report, that theory has gained credence given the expanded search area off Malaysia's west coast.
The search began in the South China Sea and Gulf of Thailand, on the approach to Vietnamese airspace.
Since then, Malaysian authorities have widened the search radius several times as well as shifting its focus, fuelling accusations of official bungling and a slow-footed response.
Authorities have not said whether they have any firm indications that the plane might be in the Andaman Sea.
Vietnam suspended its air search and scaled back a sea search today - awaiting clarification from Malaysia about the potential new direction for the search, which involves dozens of ships and aircraft from several countries including China and the United States.
There have been several false alarms linked to debris spotted in busy shipping lanes in Southeast Asian waters.
Large oil slicks found by Vietnamese planes on Saturday yielded no trace of the plane, nor did debris found Sunday near Tho Chu island, part of a small archipelago off southwest Vietnam.
Malaysia sent ships to investigate a sighting of a possible life raft on Monday, but a Vietnamese vessel that got there first found only flotsam.
Chemical analysis by Malaysia on Monday found no link between the oil slick found at sea and the missing plane.
Revelations that two of the passengers were travelling on stolen EU passports fuelled early speculation that the plane was the victim of a terrorist attack.
Malaysia's national news agency, Bernama on Sunday quoted Home Minister Datuk Seri Ahmad Zahid Hamidi as saying the two suspect passengers had "Asian features", without elaborating.
It emerged on Tuesday that the pair appear to be Iranian illegal immigrants who were seeking a new life in Europe.
Chinese media have reported that relatives have heard ringing tones when trying to call their missing loved ones' mobile phones.
The accounts of some passengers on Chinese messaging tool QQ show they had been online, other reports say, although the operator says that failure to shut the software down properly can give that impression.
Alfred Siew, a Singapore-based technology commentator, admits it is a "mystery", but said the matter could be merely due to a network error affecting some phones.
Datuk Azharuddin Abdul Rahman, head of Malaysia's Department of Civil Aviation, said Monday that five passengers who had purchased tickets and checked baggage did not make the flight.
He told journalists their luggage was removed from the plane, as per standard procedure, when routine checks indicated the five passengers had not boarded before take-off.
But Malaysia's chief of police Tan Sri Khalid Abu Bakar insisted yesterday that all passengers who booked the flight did board in the end.
However, muddying things further, Malaysia Airlines issued a statement hours later saying there were indeed four passengers who had valid bookings but did not check-in for the flight.
Malaysia's civil aviation chief, Azharuddin, also drew scorn on social media by referring to black Italian footballer Mario Balotelli when discussing the two suspicious passengers who boarded the plane with stolen passports.
When asked what the two suspects travelling on EU passports looked like, Azharuddin referenced Balotelli, who was born in Italy to Ghanaian parents and is an Italian international player, as an example of how one's skin colour does not necessarily indicate nationality.
Malaysia's transport ministry later issued a statement saying "no ill feelings" were meant by the comment, but the social media reaction underlined feelings of embarrassment with so much world attention focussed on the plane search. – AFP, March 12, 2014.