Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - Netherlands - 1937 (June 5-20), 6 mixed franking covers of KLM Direct and Return ''New Tariffs'' Flight Amsterdam - Bandoeng - Amsterdam, including 4 with Charity pre-print ''For Benefits of National Aviation Fund'', posted into the mail at Bodegraven, Gravenhage, Leiden and Naarden, 2 with Air Mail pre-print or plain envelopes sent from Amsterdam Central Station or Scheveningen, each one franked by 2-6 Dutch adhesives and uprated by Indies Queen Wilhelmina 20c red lilac on reverse, flight markings on front and back, VF, Est. $400-$500, Scott #144, C10