Germany recruited both death-row criminals & ultra-loyal SS troops to fly them (baling out once locked onto the target)
I have read that the members of the "Leonidas Squadron", formally known as 5th Staffel of Kampfgeschwader 200 were not all as has been suggest above. Many were relatively normal people. Why they were willing to consider suicide missions was simply due to the fact that their chances of dying were relatively high even in non-suicide missions plus they were desperate to stave off the defeat of Germany (and thus fearful fates for their families etc - remember that this was after the Allies Unconditional surrender conditions and the Morgenthau plan). Therefore, why not simply accept the fate that you were going to die anyway and thus take on a mission that gave you a much higher chance of making that death one that had a major effect in the battle.
That said, trying to extend that philosophy to other nations/environments that don't have the same scenario might be a stretch.
