Related Clues:

• Unwelcome giveaway
• Device increasing drag
• Alert follower, perhaps
• Information that ruins the ending
• Elizabeth I after kisses, upset about nothing -- movie-goers don't want to see that
• Agents about to steal painting -- it could ruin everything
• Oxygen needed for rearmost European in football team on plane, one flapping
• Flying control surface
• Movie reviewer's no-no
• Aerofoil on a fast car
• One line in translated prose, a giveaway of what's to come
• 'Darth Vader is Luke's father,' e.g
• Returning engineer flaps about nothing — one who says too much
• 'Rosebud is a sled,' e.g
• Aerofoil at the back of a car to reduce lift at high speeds