At this momemnt in time there are no flights out of Bulawayo to either Vic Falls or Livingstone. Air Zimbabwe is operating again but it is a very unreliable service so don't count on it yet.
Things are changing quite quickly within the area though and by next year there could well be flights on this route back up and running.
There is a very good bus service called Pathfinder that operates this route daily. Nice buses and reliable service and relatively cheap.
So wait for a bit see what happens with flights and if nothing go on the bus.