Aircraft interior configuration

An interior configuration for an aircraft, comprising:

• a first passageway extending along a longitudinal axis of a fuselage of the aircraft;
• a second passageway extending along the longitudinal axis;
• and
• a transitional region disposed between the first passageway and the second passageway;
• wherein the transitional region extends perpendicularly to the longitudinal axis, between first and second sides of the fuselage, the first and second sides being disposed on opposite sides of the longitudinal axis, and
• wherein the transitional region is configurable from at least a first configuration to at least a second configuration.