I'll just give my two sense on spit fires change in personality: The wonderbolt academy is pretty much a bootcamp, and in bootcamps, the drill sergent pretty much has to be rough on recruits. when you meet a drill sergent outside of the boot camp, they actually usually prove to be nice people, but have to act like jerks to round in the recruits, which is what I felt Spitfire was doing: she's nice most of the time, but in the academy, she has to toughen the recruits up so they follow orders.