1910 Aviation Week (5-12 June) at Mondorf, colour ppc for the event picturing airplane and noted as one of the first trials, with 5c Arms tied by rectangular boxed Mondorf les Bains / Champ d’Aviation (airfield) ds, sent to Walferdange (bs next day), a rare early Luxembourg airmail item, very fine (Mü. 2, 20’000pts)