Airplane flights are not a trivial problem.
So many variables in price and availability. You can get a better deal sometimes routing way out of your way than a direct flight, and prices change all the time. Naturally, your meeting place would have to have a large airport.
Driving is a bit easier. I'd suggest the easiest way to deal with this is to put dots on a map, and basically look where the middle of the pattern is. Then the most important factor involves access to reasonable lodging.