A wing (3, 3') for an aircraft, comprising: - a wing box defining a first wing profile with a first leading edge, a first trailing edge opposite to said first leading edge, a first top surface and a first bottom surface opposite to each other and extending between said first leading edge and first trailing edge; said first leading edge and first trailing edge having a longitudinal extension along respective first axes spaced out from each other; - a first movable appendage (21, 21') hinged on said wing box and defining a second wing profile, in turn comprising an end wall and a second trailing edge opposite to each other, a second top surface and a second bottom surface opposite to each other and extending between said end wall and said second trailing edge; said first movable appendage (21, 21') being movable with respect to said wing box between: - a first position, wherein said first and second wing profiles (35, 28) are contiguous with each other, and at least part of said second bottom surface and second top surface define respective extensions of said first bottom surface and first top surface (32, 31); and - a second position, wherein said second bottom surface and second top surface are respectively separated from said first bottom surface and first top surface (32, 31); said wing box comprising a first spar having a curved section in a plane orthogonal to the associated first axis; characterized in that said end wall is curved and arranged to abut against said first spar at least along said second top surface and said second bottom surface, when said first movable appendage (21, 21') is in said first position. - a wing box defining a first wing profile with a first leading edge, a first trailing edge opposite to said first leading edge, a first top surface and a first bottom surface opposite to each other and extending between said first leading edge and first trailing edge; said first leading edge and first trailing edge having a longitudinal extension along respective first axes spaced out from each other; - a first movable appendage (21, 21') hinged on said wing box and defining a second wing profile, in turn comprising an end wall and a second trailing edge opposite to each other, a second top surface and a second bottom surface opposite to each other and extending between said end wall and said second trailing edge; said first movable appendage (21, 21') being movable with respect to said wing box between: - a first position, wherein said first and second wing profiles (35, 28) are contiguous with each other, and at least part of said second bottom surface and second top surface define respective extensions of said first bottom surface and first top surface (32, 31); and - a second position, wherein said second bottom surface and second top surface are respectively separated from said first bottom surface and first top surface (32, 31); said wing box comprising a first spar having a curved section in a plane orthogonal to the associated first axis; characterized in that said end wall is curved and arranged to abut against said first spar at least along said second top surface and said second bottom surface, when said first movable appendage (21, 21') is in said first position.