flyer buff not stackable?

In this game there are 2 tipes of buff, active and in combat buffs.
Active buffs give bonus stats at the start of the turn, they can't stack and are the buff that affect bladetome dmg, hone and fortify give active buffs.
In combat buff are invisible buffs that activate only when the character fights, they can stack, don't affect bladetome dmg and can't be reversed by panic effect, those buffs are given by spurs, goads and wards.