In the 377 Stratocruiser's main passenger cabin, 18 seats could be made up into nine lower double berths. Nine upper single berths could be lowered, already made up and ready for occupancy. The interior sidewalls, ceilings upholstery and floor coverings were all fabric-covered for sound purposes and weight. Only the surfaces in the galley, bars and toilet areas were hard. The peaceful, light-toned colors of the interior were designed to help passengers' eyes adjust to the bright sunlight above the clouds.