During the interception of a medium UFO with 100% victory chance on auto-resolve, I chose auto-resolve. The UFO was downed, but the health of my two interceptors showed 0% (fuel and ammo indicated "--") and the squadron was no longer displayed on the geoscape, most likely destroyed despite the 100% victory chance.
But when I checked the squadron base immediately after the interception, the supposedly destroyed aircrafts were there, safe and sound and ready to roll.