As parkour is a single player gamemode, we decided to let VIPs to fly in parkour server as if they cheat and fly, they wouldn't be affecting others game-play. However, flying in parkour is completely optional and if you don't want to cheat and make our parkour courses legit just do /fly again to disable the fly mode

Or you can do as some VIPs do that if its too hard you can "create your own checkpoints" by flying to the last imaginative checkpoint you created before you lost... I don't know, its up to you