Description: Registered Letter by Air Mail: PRAGERSKO - BUENOS AIRES, ARGENTINA 07.04. 1939. ZEMUN 5 transit cancellation for 08.04. 1939 and an undated Buenos Aires registration marking on reverse. German South American service cachet in red to obverse. It is likely that this item was carried on Flight 443 (Seaplane ‘Nordmeer’, Graue-Duggan) leaving Frankfurt on 13.04. 1939 and arriving in Buenos Aires on 16.04. 1939. The franking of Din. 38.00 is underpaid by Din. 1.00 - Foreign Letter Fee (Din. 4.00), Registration Fee (Din. 4.00) and Air Surcharge to 5 gr. for Argentina (Din. 31.00).