First, what do you know about global warming? --"carbon footprint" (I am beginning to hate reading and saying that:) please don't use those words in your paper...) "vapor trails and global warming," just anything your know about it...write it all down - scribble if your must. Does anything jump out at you? Good! Write about that as your thesis, and make it an argument for or against.
all made up, so do not use this>> "Over one million aircraft take to the skies each day, each of which causes 13oo pounds of noxious gas to be carried into the atmosphere. With over 200 million passengers seeking air travel, it is impractical to suggest shutting down the entire operation, but more consideration toward lessening the impact of aviation on the planet must become a top priority in the war against global warming."
This is not at all a strong enough statement for your paper - it is merely an example of a thesis.
I look forward to your essay submission!