This would depend mainly on the altitude you were flying at and the ascent and descent angle from that height.
I have assumed that holding patterns don't count and that you didn't have to detour around any mountains etc.
That is, you flew directly to your destination.
Also, you have not made it clear whether the 2000km is the ground distance or the air distance.
Anyway, the air distance would be slightly more than the ground distance.
+118654 
