Wings can be held up by wires or braces on the fuselage and they are also supported by their internal structure. Components that are concealed under the aluminium or composite wing casing include ribs and stringers. The former run parallel to the fuselage and are attached at regular intervals along the wing. The latter run along the length of the wing and connect the ribs. Support is also provided by the spar, which runs parallel to the stringers. An aircraft’s fuel is sometimes stored between the ribs and this too can lend more rigidity to the wings.
Answered by Mike Simpson.