Happened to me with 4.11.1m and DGen_mod 126.96.36.199. Not intended as an anomaly; just curious.
After a mission during which I shot down two Emils, close to home base I saw what seemed another one, from nowhere. It was, instead, one of the two that with unseated pilot (like horse with no rider during Siena's Palio
) had wandered until my air base and that I left, after having landed and immediately before ending mission, still flying! Actually in debriefing I got only one kill!