It's not really an issue.
Short haul a/c -like most a/c- can either
1. Be filled up with fuel
or
2. Be filled up with payload- pax or freight
but never- filled up with both!
So for a short haul a/c to be delivered- fill it up with gas -no payload at all, and away you go!
All that remains is a little applied route planning. Another consideration is that as delivery flights are 'non-revenue', some limitations dont apply.
For example an ERJ-145 in service is restricted to FL370 (due to a limitation that's related to emergency descent times/ pax oxy duration etc)
But regularly ferries at FL 410. Better range due lower fuel burn etc.