Initially, the space behind the flight deck on early variants was so small that it only housed crew quarters and avionics racks. As aerodynamic testing showed that stretching the upper deck profile reduced drag, Boeing added extra seating capacity, eventually expanding the hump across subsequent production generations. Related Inside The Boeing 747's Upper Deck Layout From a secluded cocktail bar to a high-density seating zone, the evolution of the 747's upper deck reflects the changing priorities of aviation. Related The Boeing 747 Was Never Supposed To Be A Passenger Jet: What It Was Truly Designed For The original designs for the Boeing 747 were made with a different purpose in mind. The raised cockpit resolved a critical logistics bottleneck, allowing front-loading freight operations to exist without compromising structural pressure boundaries or flight deck access.