The cheapest i flight i know is tiger airway which flies you from singapore to phuket for $68 SGD.http://www.tigerair.com/sg/en/

The distance from singapore to phuket is 1344km. http://www.distancemonk.com/Singapore/Phuket/15+hours+27+mins/1344.395/

which means you are paying only for 0.05 $ / km. I couldn’t find any flight cheaper than this.

Thats slightly different. A 180 seat A320 airliner is not bizjet. I still believe the Kan Air flight is the cheapest bizjet/private jet/exec jet (whatever you want to call it) flight in the world ever. Its still operating some of Kan Air’s sectors now.