Maybe this isn't the best idea, but perhaps Afterburners could go in the action list at the bottom, as a free action that's only available while you count as flying? And activating RBJJ makes you count as flying when you first activate it, ending when you move as per usual? At least it might help with the possibility of accidentally activating then not using the ability since you can preview your flight distance from RBJJ like normal before choosing to activate Afterburners. Idk, just a suggestion, but again I'm not sure how well it would work out so take it with a grain of salt ^-^