Questions over flight path oversight
23 July 2014 Last updated at 06:56 BST
The loss of Malaysia Airlines flight MH17 has raised questions over how international flight paths are managed.
Prior to the crash airlines were not warned against flying over eastern Ukraine, by the European regulator Eurocontrol, which said it was following guidance from Ukrainian authorities.
However some airlines chose not to fly over that region.
From Singapore, Mariko Oi looks at the issues surrounding flight paths.