Please explain your feature request to the best of your abilities:

If a player is outlawed, enemy, or at war. Disable rocket or elytra use, this would allow a server to still utilize elytra's but not allow them to abuse Towns and Nations.
Or disable them from entering or leaving the base when elytra is equipped.

During our war players were just flying over with elytra's and griefing/stealing with TNT and flying away. It's not a huge deal but it would keep the battle outside first.