6 air mail letters November-December 1941 from Netherlands to USA including November 18 (German censor Frankfurt am Main) to New York, through Lisbon, Bermuda (held by UK), returned to UK, purple released by british/ censor/ jan 1946 and arrived March 4, in New York, label Terug afzender etc. (return sender), blue Zurück Postsperre, blue retour Postverkehr eingestellt and more