 The covers were then backstamped and returned to their senders as promotion of the Air Mail Service.In 1929–1931, Lindbergh carried much smaller numbers of souvenir covers on the first flights over routes in [[Latin America]] and the [[Caribbean]], which he had earlier laid out as a consultant to [[Pan American World Airways|Pan American Airways]] to be then flown under contract to the Post Office as Foreign Air Mail (FAM) routes 5 and 6.