The disappearance of Flight MH370 is one of the most sophisticated, well-planned and well-orchestrated hostile takeovers of a plane since the 9/11 attacks in the United States 13 years ago, aviation and security experts said.
Malaysian Prime Minister Najib Razak declined to label the disappearance of the plane as a hijack but experts added that the people behind it had a clear mission and did all the right things.
"If this was a man-made event, the perpetrator was very knowledgeable about what to do," said Mr Jacques Astre, president of International Aviation Safety Solutions and a former United States Federal Aviation Administration official.
Eight days after the Malaysia Airlines jetliner went missing, its whereabouts remains a mystery.
About half an hour after the Beijing-bound flight left Kuala Lumpur with 239 people, air-traffic control lost contact with the Boeing 777-200ER aircraft.
It has now been established that the plane's transponder - a device that emits signals to tell air-traffic controllers where the aircraft is - was deliberately turned off.
The plane's Aircraft Communications Addressing and Reporting System, which transmits text messages and data, was also shut down.
Only someone with in-depth knowledge of the B-777 would know where the controls and systems are located and how to deactivate them.
To turn off the transponder for example, one would have to cut a circuit breaker which is found above and behind an overhead panel.
Though contact with civilian aviation controllers was cut off while the jetliner was between the waters of north-eastern Malaysia and southern Vietnam, Malaysian military radars managed to detect MH370 making an unplanned turn. It then travelled west back over Peninsular Malaysia before flying in a north-westerly direction.
For close to seven hours after that, the plane continued to fly, seemingly undetected. Satellite data reportedly showed the plane flew as high as 45,000ft at one point - higher than normal cruising altitude - turned sharply to the west, came down unevenly to 23,000ft as it neared Penang and then turned again while climbing to a higher altitude.
"It looks like the aircraft followed airways on the alternate route probably in an attempt to avoid attention by air traffic," said Mr Astre.
The altered flight path the aircraft took is one that typically leads to Europe and the Middle East.
Mr Philip Baum, managing director of Green Light Limited, a London-based aviation security training and consultancy company, said: "The industry is completely dumbfounded. If this was a terrorist plot, then it's a very well-orchestrated and highly professional job, like 9/11 was."
On Sept 11, 2001, terrorists hijacked three planes and crashed them into the World Trade Center in New York and the Pentagon building in Virginia.
Almost 3,000 people were killed, most of them in New York, when the burning towers collapsed.
The erratic movements of MH370 as captured by satellite data could suggest two things, experts said.
Cockpit crew - whether the pilots, or others who had taken over the cockpit - could be trying to avoid radar detection, said Mr Michael Daniel, a retired United States Federal Aviation Administration official.
"You can't have such change in directions unless done manually and deliberately," he said.
Alternatively, there could have been a struggle in the cockpit, said Mr Paul Yap who heads Temasek Polytechnic's aviation school.
He added: "It's possible there was a struggle and this could have been between the pilots and hostile passengers or between the pilots and crew if indeed the plane was taken over by the airline staff."
As investigations take a dramatic turn with the focus now on the pilots and cabin crew, the potential hijack of MH370 has once again put the spotlight on everything that is wrong with aviation security.
Mr Baum said: "The whole issue of the stolen passport and that we do not know who is boarding an aircraft really does need to be addressed if we want to be serious about aviation security."
It has been confirmed that at least two passengers on MH370 were travelling on stolen passports.
Cockpit security is another area that needs to be beefed up, Mr Yap said.
"There are security procedures in place and we must make sure that airline crew follow these procedures and do not become complacent."
Photos taken in 2011 of MH370's first officer Fariq Abdul Hamid, 27, with another pilot and two women in the cockpit have recently been leaked.
While there may not have been a security risk, it clearly showed complete disregard for procedures, Mr Yap said.
Mr Baum said: "What happened to MH370 again demonstrates that the aviation security procedures that we have put in place at airports around the world are not as professional as the opposition we are up against.
"We must become more intelligent about the way we make judgments about people based on the potential risk they might pose, instead of being concerned about whether or not they are carrying liquids, gels and aerosols."
