From AMS Glossary
(Or distrail.) A clearly delineated limpid lane forming behind an aircraft flying in a thin cloud layer; the opposite of a condensation trail.
The heat of combustion of the aircraft fuel, released into the swept path by the exhaust stacks of the aircraft, can, under certain conditions, evaporate existing clouds (if not too dense) and yield a distrail. Clouds of low liquid water content and relatively high temperature are susceptible to distrail formation but the phenomenon is comparatively rare.