Since you have to spend time researching pick something you are interested in or the project will be more miserable.
Mandatory national service is a possible topic (and an argument.) If it's expository, pick an aspect of military aviation of interest to you. What about the evolution of air weaponry; the aspect that modern weapons are more ethical as they are more precise would make it argumentative, or you could write on the evolution of navy planes (which would mean reading some scientific articles--but you might find it interesting.)
You could write about defense weaponry and fill out your paper with some possible defense situations (what ifs.)
Make sure that you stick to structural conventions in your paper--all those topic sentences, etc. add up to a higher grade.