One is a technical wizard whose affable manner made him a favourite of trainee pilots; the other an enthusiastic young aviator planning to marry his sweetheart.
The captain and co-pilot of Malaysia Airlines Flight MH370 are now at the centre of a baffling paradox: as circumstantial evidence mounts that at least one of them may have been involved in the plane's disappearance on March 8, accounts of their lives portray them as sociable, well-balanced and happy.
Described as devoted to their families and communities, neither fits the profile of a loner or extremist who might have a motive for suicide, hijacking or terrorism.
International media scrutiny and investigations by the Malaysian police have failed to turn up red flags on either the captain, 53-year-old grandfather Zaharie Ahmad Shah, or the co-pilot, 27-year old Fariq Abdul Hamid.
Both live in well-to-do neighbourhoods in Shah Alam, an area west of Kuala Lumpur that is popular among flight crews for its proximity to the international airport. On Tuesday, security guards prevented reporters from entering Zaharie's upscale gated residence. About 10 minutes' drive away, Fariq's house stood empty, with an unread newspaper lying outside.
Family and friends say there is nothing in their personalities or past to suggest they would have committed foul play.
"I've never seen him lose his temper. It's difficult to believe any of the speculation made against him," said Peter Chong, a friend of Zaharie, describing him as highly disciplined and conscientious.
Eleven days after the Boeing 777 jetliner carrying 239 people vanished without trace, scrutiny has zeroed in on the pilots due to the deliberate way in which the plane was switched into radar darkness and diverted far from its route to Beijing.
The person who chose that exact time and place to vanish appears to have acted only after meticulous planning and must have had advanced aviation knowledge, according to experts.
"It raises so many questions, not least that you have got to be prepared to believe that a pilot would do this," said Paul Hayes, a leading air safety expert at UK-based consultancy, Flightglobal Ascend.
"But it is hard to understand the motive. In cases where pilot suicide was thought to be the cause, the alleged suicide pilots executed the plan as soon as they were in a position to do so."
A HANDYMAN WITH POLITICAL PASSIONS
Lacking other explanations, focus has turned to what would otherwise be seen as innocent passions in Zaharie's life - a desire to vote out Malaysia's long-ruling government, and an extreme enthusiasm for flying planes and fixing gadgets.
Zaharie, a balding father of three who likes to cook, appears to have undergone a social-media awakening in early 2013 when he began posting video of himself on YouTube, dispensing tips on how to fix refrigerators and tweak air conditioners.
After signing up to YouTube in January 2013, the man described by friends as a moderate Muslim watched clips on God and atheism and speeches by Malaysian opposition leader Anwar Ibrahim. He joined Anwar's party the same month, and helped campaign for elections in May 2013 that were narrowly won by the ruling coalition and afterwards disputed by the opposition.
"There is a rebel in each and everyone of us...let it out!" Zaharie wrote on Facebook in the weeks after the election as Anwar led nationwide rallies to challenge the result.
About six hours before Flight MH370 took off, Anwar was convicted and sentenced to five years' jail for sodomy, a ruling widely condemned as politically motivated.
That has sparked speculation that Zaharie, perhaps enraged by the setback for his political idol, could have brought down the plane as a form of protest or out of despair.
But his passion to see Malaysia's first change of government in 56 years was shared by millions in the country and the opposition is a democratic movement with no links to extremist groups. There is no evidence he attended Anwar's trial, as some media reported. He still lived with his wife, despite other reports they were breaking up.
"He was a disciplined person," said Chong, who said he first met Zaharie two years ago when he saw him tidying chairs after a community event.
"Since 9/11, I believe they are not even allowed to open the cockpit door even under duress. The captain Zaharie that I know would be the kind of person who would strictly stick to that."
Zaharie made no secret of his obsession with aviation, which ranged from flying model aeroplanes to setting up a multi-screen flight simulator at home, which he also showed off on YouTube. Police have seized the machine and are examining its contents, but say they have yet to find anything suspicious.
A fellow Malaysia Airlines pilot, who declined to be identified, described Zaharie as a "decent and approachable man" who was sought out by less experienced pilots to observe their final training runs, a procedure known as line checks.
"Younger pilots would seek him for their line checks because he was easy to talk to," the pilot said.
Neighbours who know Fariq, the son of a senior civil servant, told Reuters he is known as a good and pious man who was a regular worshipper at a mosque a few minutes walk from his house. Relatives said he was a diligent student who loved his job, having recently qualified to fly the wide-body 777 jet.
There has been no suggestion he had extremist views or serious personal problems, although he came under fire after the plane's disappearance when it emerged he had allowed two women into the cockpit on a 2011 flight.
Fariq, who officials believe uttered the final words "all right, goodnight" from the cockpit, had been expected to propose this year to his girlfriend Nadira Ramli, who was a co-pilot for budget carrier AirAsia.
"It was a matter of time before they got married," said a relative of the fresh-faced Fariq who asked not to be identified. "Police investigating the suicide theory is upsetting to the family. Why would he even do that He had a good life and he had Nadira."