According to my catalog, Russia did not release an Airmail issue in 1925. The issues were 1922, 1923, 1924 & 1927. The 1922 is an Imperf with a catalog value of $50 US if used. The 1924 issue of the Fokker depending on the variety can be worth some decent money. To know for sure, an image would need to be provided as Stamps are a visual thing and condition is everything.