1930 Nothing Discourages a Boeing 40-B4 Ad 

Model 40B-4 Mailplane Radio Ship Model 

Boeing Model 40B in Flight Above Mountain 

Model 40B with NACA Cowling 

Passengers and Pilot with the Boeing Model 40B Transport 

Boeing Model 40B flying over mountain 

Boeing Model 40 with Special Passenger 

Model 40B with Passengers 

B-17s Modified as YB-40s at Douglas' Tulsa Plant with B-25s and A-24s 

Eddie Allen in the Cockpit of a Model 40B-4 

Model 40B-4 at Plant I Hangar 

Model 40B-4 Mailplane Manufacturing 

Model 40B at Boeing Hangar 

Model 40B mailplane