Aircraft cabin environment

A seating plan for an aircraft comprising:

• said aircraft having a generally cylindrical interior volume having a forward nose portion and a rearward tail portion defined by a frame, the volume being longitudinally separated by a floor into a lower cargo hold and an upper passenger cabin;
• two side seating area adjacent to side wall of said frame each one of said side seating areas having a first multiplicity of chair rows wherein the first multiplicity is configured to extend lengthwise through said passenger cabin and the first multiplicity is affixed to said floor;
• a midsection seating area having a second multiplicity of chair rows wherein the second multiplicity is configured to extend lengthwise through said passenger cabin, the second multiplicity of chair rows being vertically displaced relative to the first multiplicity of said side seating area and each of the second multiplicity comprises at least three adjacent chairs, wherein the at least three chairs of each chair row of the second multiplicity have a pitch of greater than 33 inches;
• and
• two parallel aisles extending lengthwise independent of stepped gradation therealong through said passenger cabin, each of said two parallel aisles allowing simultaneous access to the first multiplicity of chair rows of one of said two side seating areas and the second multiplicity of chair rows of said midsection seating area at least one ladder in one of said two parallel aisles and extending vertically from said floor to the second multiplicity.