Look to the aircraft used by Bush Pilots for small aircraft that could be stored in a Bolt Hole. Many are small, can be reconfigured for landing on water, airfield, or even snow and require the one thing the Project needs. The need a single pilot and are easily acquired and most importantly won't be missed! Not really all that good for cargo but for small scale troop transport or scouting they would do the job quite well.
http://en.wikipedia.org/wiki/Bush_plane