 14 pilots were taken on from the Post Office Department and the service over the Allegheny Mountains began 1 September, initially with Curtiss Carrier Pigeons, quickly supplemented by 18 Douglas M-2s taken over from the Post Office.In early 1928 NAT added eight Travel Air 6000s.NAT passenger flights between New York (Newark) and Chicago began in December 1930, one Ford Trimotor a day each way.