For Soviet aviation, it has the same significance as the DeHavilld D. H. 82 "Tiger Moth"; for the Royal Air Force and all other Air Forces in the Commonwealth of Nations in WWII. A construction from 1931. Without this airplane and training in the countless flying clubs of the DOOSAF, the USSR would not have been able to withstand. As small and inconspicuous as this thing is, it was even flown as a night bomber. There was a regiment of women called the "witches of the night"; by the Germans.
https://en.wikipedia.org/wiki/Night_WitchesThere is one book namend "The Sky Remains Ours" by Marina Pavlovna Chechneva
https://en.wikipedia.org/wiki/Marina_ChechnevaIn this book she vividly and with a lot of feeling describes how she and her comrades flew and fought. It's one of the autobiographies that won't leave you cold.