This P-51 Mustang was used for training experienced german pilots how U.S. aircraft responded  during engagements. This Aircraft also had its belly painted yellow so the german anti aircraft crews would not shoot them down while flying.  The 2nd Staffel had special groups that would disperse to the scene of a downed U.S. plane to recover fuel and parts to keep These"Birds" flying(which was by all means no easy task, US fighters often straithed there downed planes).