The relevant title (ie flight plan) indeed has 22 letters, but nowhere can I see them in any connected form. There is so much thematic stuff going on that I can't believe we just have to colour in the letters as we come across them in the completed grid.
having trouble identifying the 22 cells. Are we looking for a title and, if not, is it a variety of items or just the same one repeated? Also not sure how 25d ends. Same as its first letter or its third?