DoubleJump is plugin, as the name suggests, allows players to do "double jumps" in hubs and lobbies.
Thanks Fabricio20 for the plugin idea.
doublejump.jump - Allows to double jump. Setting this permission to false may requires the flight to be disabled. Bear in mind.
doublejump.admin - Allows to use the reload command.
/doublejump reload - reloads config file (doublejump.admin)