villain and work your way up to the main one in a sequel?

With the Nolan trilogy, we started with Ra's al Ghul and Scarecrow first then went to the Joker in the second movie.

Iron Man: Iron Monger first, Whiplash and Justin Hammer second, with the third one now we're getting the Mandarin.

You know it really depends on the franchise. With some, I think it's better to set him up in the first movie, and to go with a "beginner" enemy (not to say they're weak, but you need room to escalate the conflict).

With others, they are so integral to the premise, that you need them in the first movie.

I'll say it's entirely dependent on the character, the hero's relationship with the villain, the origin, and the overall story1. FIELD OF THE INVENTION
The present invention relates to a system for collecting and recovering de-icing fluid that is sprayed onto an aircraft.
2. DESCRIPTION OF RELATED ART
The formation of ice on the wings of an airplane can reduce the lift and increase the drag by degrading the performance of the airfoil. Additionally, the ice may break away from the wing and be ingested by an engine, possibly causing a failure of the engine and endangering the safety of the passengers of the aircraft. To remove and prevent the build-up of ice on the wings, the skin of the wings can be sprayed with a fluid that has a low freezing point, such as a glycol. In cold climates the wings are typically sprayed at the airport before takeoff.