Air Post Semi-Postal issues. 1931, Charity issue ''Aizsargi I'', surcharges in violet, blue or red on the third Air Post issue, 50s/10s-1.50L/25s, complete set of three triangle stamps in blocks of seven, full OG, NH or LH (one stamp in each block), VF, C.v. $619 as singles (Image)

Air Post Semi-Postal issues. 1932, Charity issue ''Aiszargi IV'', 10(20s)-25(50s), perforated and imperforated complete sets of three triangle stamps in blocks of seven, full OG, NH or LH (one stamp of each block), VF, C.v. $975++ (Image)

Air Post Semi-Postal issues. 1932, Aviation Pioneers, Icarus, Leonardo da Vinci, Balloon and Airplanes, 5(25s)-25(1.25L), perforated and imperforated complete set of five, blocks of four, many with sheet margins, full OG, NH, VF and scarce multiples, C.v. $1,300 as singles (Image)

Air Post Semi-Postal issues. 1933, Charity issue ''Aviation Pioneers' Fund III'', 3(53s)- 35(1.35L), perforated and imperforated complete sets of triangle stamps in blocks of four, full OG, NH, VF, C.v. $1,100 (Image)

Air Post Semi-Postal issues. 1933, Charity issue ''Aviation Pioneers' Fund IV'', Airplanes and Zeppelin, 8(68s)-40(1.90L), perforated and imperforated complete sets of four, sheet margin blocks of four, full OG, NH, VF, C.v. $2,200 as singles (Image)