Hello Rick,
Easy Way:
I suspect if it is an mdl file in the aircraft folder, a figure could be added via a DP file mount entry.
Not so easy way:
If it is a scenery bgl file, a figure could be added (from another bgl having a crew figure) via scasm editing (too difficult for me with older bgl file versions though), or a figure redesigned into the original jeep scource file.
O