Cover franked with block of four and single 1924 4c plum 'San Martin' issue (SG 533) tied by VIA AEREA BUENOS AIRES cds's dated 28 MAY 1926 with manuscript 'Via Aerea' at top left. Addressed to MONTEVIDEO, URUGUAY with arrival cds dated the same day on reverse. This cover was flown by the Junkers Mission that ran the Buenos Aires - Montevideo route between March 1926 and October 1927. Scarce.