souvenir sheet issue "export fair Hanover", on registered airmail as First Day Cover cancelled Hanover general. export fair 22.4.49 to Hamburg, with lilac box cancel "1. Measured-flight 22-4-49", blue "BEA special route: . " and red flight stamp, reverse green hand stamp "BEA fair Luftdienst. " as well arrival postmark Hamburg 23.4.49, very fine, Michel 500.-