Yeah, try this: make up a plane out of cardboard, make it look as real as can be, maybe with real life uses in mind.
I did that in the 8th grade for a school contest, I got 1st place; but then so did a bunch of other "talented students."
I made up a concept hypersonic airliner made from model rocket cones and tubes, paper, masking tape, etc... It wasn't designed to fly, just a model. It was 29 inches long and I still have it and it's ribbon -- they're both eight years old now.
Or you can always make an RC, let your imagination soar.
Hope this helps, good luck
The meaning of life is curiosity; we were put on this planet to explore opportunities.