External lighting, as jmig says, is a no go as far as regulations go.
Internal (flight deck) lighting might be worth you exploring. Glass cockpit displays normally have auto-brightness built in but analogue instruments don't. You could also apply it to switch lights / legends - you will normally find a dim / bright, night / day two position switch but not an automatic dimming system.
Bear in mind that this is a theoretical exercise to show that you can apply what you have learned on your course not a task to design a product for certification and installation on an aircraft.