Data Are For Revenue And Non-Revenue Miles Flown. Source: Data For 1931-1939: U.S. Department Of Commerce, Air Commerce Bulletin. Data For 1940-1941: Civil Aeronautics Administration, Civil Aeronautics Journal.
This NBER data series m03071 appears on the NBER website in Chapter 3 at http://www.nber.org/databases/macrohistory/contents/chapter03.html.
NBER Indicator: m03071
Release: NBER Macrohistory Database
National Bureau of Economic Research, Revenue and Non-Revenue Passenger-Miles, Domestic Airlines for United States [M03071USM429NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/M03071USM429NNBR/, September 4, 2015.