It should be changed with certain conditions such as:
If a town has PVP toggled on, /tfly cannot be enabled.
If a town is engaged in a war, /tfly cannot be enabled.
I can mostly see people whining of /tfly because they can't kill their targets while they're flying. It is still towny and I don't really see the problem with people flying around the town since its only purpose is traversing around the town faster and building easier.
Because if we disable this, donators can still fly and they have the advantage in PVPs.