These were the only U. S. built commercial aircraft able to cross the Atlantic with a payload until the arrival of the Douglas C-54 Skymaster in November 1942.
Razlika tlakov je bila 2,5 psi (17 kPa), kar pomeni, da je bil na višini 14 700 čevljev (4 480 m) tlak v kabini 8000 čevljev (2440 m).