Flight from Bishkek to Urumqi

Hi everyone

Is it possible to get a flight out of Bishkek to Urumqi in Xinjiang, China? How often are these flights and how much should they cost? I'm having trouble finding any information on the Thorn Tree, and want to make sure I can do this route before leaving Osh for Bishkek.

My alternative is to overland via Irkeshtam Pass and Kashgar, but I've already travelled a large part of this road coming from Tajikistan and definitely do not want to do it again - the road conditions were horrendous :)

Cheers and thanks for your help

Troy