.... hmmm, without giving it too much thought, I think the wing is rather indifferent to the path of the a/c relative to the earth, so will still be generating lift, whether or nor the a/c is straight and level, inverted, vertical, etc. (assuming a positive A of A) So say an a/c in a vertical trajectory would all things being equal, have the nose slightly off vertical so the 'weight' could counteract the lift vector, or be flying with a A of A of exactly zero. Where the hell is my copy of Kermode when I need it.
Anyone actually flown vertical have a better answer?