Soviet Union: Airmail labels

Here are old airmail labels from Soviet Union. There were so many airmail labels issued in Soviet Union.

Year:  1928, Gummed. Günter Mair's catalogue no: - SOV-A-8a, perforated 11 ½ , sheets, "Par avion" modified, some sheets come imperforated, issued at Leningrad, orange-red/cream, 4****

Year: 1932, Ungummed. Günter Mair's catalogue no: - SOV-A-25a, perforated 10 ¾ , sheets of
50(5x10), black/light grey, 4****

Year: 1933, Ungummed. Günter Mair's catalogue no: - SOV-A-36, perforated 11 ½ , sheets of
42(7x6), intended for express airmail, black/light greenish grey, 5*****

Year: approx.1935, Ungummed. Günter Mair's catalogue no: - SOV-A-40, rouletted, sheets of
64(8x8), carmine/light grey or cream, 5*****