A wing assembly for an aircraft, comprising: a center wing structure, including: a pair of center wing outboard ends and a pair of engine mounting locations respectively on opposite sides of a wing centerline; a center wing front spar and a center wing rear spar each having a spar terminal end at each of the center wing outboard ends; and a center wing stout rib at each of the center wing outboard ends; a pair of outer wing structures, each including: an outer wing front spar; an outer wing rear spar; and an outer wing stout rib located at an outer wing inboard end; wherein the outer wing structure is generally flat and straight and has less bending stiffness than the center wing structure; wherein the outer wing front spar and the outer wing rear spar are configured to be coupled respectively to the center wing front spar and the center wing rear spar to define a wing joint coupling the outer wing structure to the center wing structure; wherein at each wing joint, the outer wing stout rib and the center wing stout rib are configured to be positioned in back-to-back arrangement and mechanically fastened to each other, wherein the center wing stout rib and the outer wing stout rib are configured to provide a load path across the wing joint from the outer wing structure to the center wing structure and accommodate differences in the bending stiffness of the outer wing structure relative to the bending stiffness of the center wing structure; and wherein the center wing structure is configured such that the spar terminal ends of the center wing front spar and the center wing rear spar at each wing joint are located no further inboard than an engine centerline associated with the engine mounting location, and no further outboard of the engine centerline than ten percent of the distance between the engine centerline and the wing centerline. a center wing structure, including: a pair of center wing outboard ends and a pair of engine mounting locations respectively on opposite sides of a wing centerline; a center wing front spar and a center wing rear spar each having a spar terminal end at each of the center wing outboard ends; and a center wing stout rib at each of the center wing outboard ends; a pair of center wing outboard ends and a pair of engine mounting locations respectively on opposite sides of a wing centerline; a center wing front spar and a center wing rear spar each having a spar terminal end at each of the center wing outboard ends; and a center wing stout rib at each of the center wing outboard ends; a pair of outer wing structures, each including: an outer wing front spar; an outer wing rear spar; and an outer wing stout rib located at an outer wing inboard end; an outer wing front spar; an outer wing rear spar; and an outer wing stout rib located at an outer wing inboard end; wherein the outer wing structure is generally flat and straight and has less bending stiffness than the center wing structure; wherein the outer wing front spar and the outer wing rear spar are configured to be coupled respectively to the center wing front spar and the center wing rear spar to define a wing joint coupling the outer wing structure to the center wing structure; wherein at each wing joint, the outer wing stout rib and the center wing stout rib are configured to be positioned in back-to-back arrangement and mechanically fastened to each other, wherein the center wing stout rib and the outer wing stout rib are configured to provide a load path across the wing joint from the outer wing structure to the center wing structure and accommodate differences in the bending stiffness of the outer wing structure relative to the bending stiffness of the center wing structure; and wherein the center wing structure is configured such that the spar terminal ends of the center wing front spar and the center wing rear spar at each wing joint are located no further inboard than an engine centerline associated with the engine mounting location, and no further outboard of the engine centerline than ten percent of the distance between the engine centerline and the wing centerline.