10.1 States that
"Your gameplay style must be fair to all players. The following are allowed[...] -Jump boosting"
I believe self-boosting is considered as jump boosting, therefore it is allowed anytime and anywhere.
Back to 1.2, which states
"Any form of cheating, hacking, or abuse of the game physics will result in suspension from the game without warning. This includes hacking of any type, score farming, or abusing a game glitch to gain an unfair advantage over other players"
So in the case of flying, if it is used against those who can't fly, then that would break both of these rules.
I think there is an exception if all members agree to allow flying (e.g. a private match, flying saw, etc.), as it acts as an agreement that the gameplay style of flying is fair to all players, thus abiding by 10.1. Since 10.1 is followed then 1.2 is automatically followed because it can't be considered abuse if everyone sees flying as fair gameplay.
However, in the end these are just opinions made by regular players. It is up to the staff members to decide the conditions that make flying or self-boosting a crime.