Methods and devices for deicing aircraft and other snow or ice covered surfaces. The invention is based on warm moisture-laden air or steam that can be released over the surface to be thawed. The device consists of three components: a hot water or steam boiler with an associated pump; a plenum for heating and humidifying air; and a delivery unit or head that brings the moisture-laden air or steam into contact with the surface to be de-iced or thawed. Various delivery heads are also described.