Did plane take remote southern corridor?
ANALYSTS say that the missing Malaysia Airlines Flight 370 is more likely to have gone south over open water than north through some of the world's most volatile countries, in order to have flown undetected.
The search for the missing plane now involves 25 countries, as it focuses on two land and ocean transport corridors where satellite data indicates the plane may have wound up after hours of flying following its disappearance.
The northern corridor passes close to northern Iran, through Afghanistan and northern Pakistan, and through northern India, and the Himalayas and Myanmar.
An aircraft flying on that arc would have to pass through air defence networks in India and Pakistan, whose mutual border is heavily militarised, as well as through Afghanistan, where the United States and other North Atlantic Treaty Alliance countries have air bases.
This corridor bristles with military radar, making it more likely that if the plane did fly north, it would not have gone far.
"If they had taken the northern corridor, they could have gone down before they reached land, so it's also possible," said Mr Mikael Robertsson, co-founder of Flightradar24.com.
The southern corridor, from Indonesia to the southern Indian Ocean, spans open water with few islands. If the aircraft took that path, it might have passed near the remote Cocos (Keeling) Islands.
Based on what is known about the flight's trajectory, investigators strongly favour the southern corridor as the likely flight path.