Abstract: The invention relates to a method for reprocessing aircraft de-icing agents comprising glycol, wherein (1) the used aircraft de-icing agents are collected in a suitable device, (2) the used aircraft de-icing agent is subsequently brought to a propylene glycol content of between 55 and 75% by weight without prior separating of solid or suspended impurities by expelling water at increased temperature, (3) the concentrated used aircraft de-icing agent thus obtained is transported to a central reprocessing system, where the same is subjected to a fine distillation, and wherein (4) propylene glycol is produced as a distillate of the fine distillation.