Question: A plane consistently missing the drop zone by c. 2.5 km/1.5 miles

[Mobhack]

I havent loaded the savegame to look at, but that makes sense.

A plane needs a certain distance to enter the map in its initial move onto the map surface. If the target hex is insufficiently far inside the map so it overflies it then the plane will make up its own mind as to where to actually drop its load.

In addition, if the plane dices and fails the drop zone aquisition it will scatter up to a KM or so from the intended point. If the scatter hex is then plotted off the map, odd things can happen - the code will try to place it on the map somewhere, which may not be where you may have planned.

So if you planeed do drop on the left edge - make the drop zone sufficiently far inside, say 5 hexes, probably more like 10-15 hexes into the right from the left edge. Same goes for air strikes at the edge, generally. Air targts right on the boundary of the map may well require you to approach from the opposite map side, or perhaps parallell to the map edge.