Nick49
Quiet a common occurance but each situ can be different. Airlines don't tend to use prop jobs such as PA31 because they are Perf C and take ages so tend to use smaller citations, sometimes King Air if only a few crew. That said i've also chartered two Challengers to get a DC10 crew from BGI to MBJ.
For a scheduled airline the easiest option can be cancel a rotation so the inbound crew can be used but this also means leaving the aircraft on ground whilst they take rest. Airlines will do anything and everything to find a way. In my current Company we've hired a biz jet just to avoid a 2 hr delay. Like i said each situ and airline is different