What is "aerosani"

An aerosani (, literally 'aerosled') is a type of propeller-driven snowmobile, running on skis, used for communications, mail deliveries, medical aid, emergency recovery and border patrolling in northern Russia, as well as for recreation. Aerosanis were used by the Soviet Red Army during the Winter War and World War II.

The first aerosanis may have been built in 1903-05 by Sergei Nezhdanovsky. In 1909–10 young Igor Sikorsky tested self designed aerosani, before he built multi-engine airplanes and helicopters. They were very light plywood vehicles on skis, propelled by old airplane engines and propellers.