This is a fairly easy Skript to setup, and requires minimal effort on your end. Follow the steps below for more clarity on how to set it up.
SETUP
When you load the Skript into your file manager, you can change the options to your liking, when ready, load it onto your server, and follow the steps below.
COMMANDS
/give-all-flight <amount> Gives everyone the specified amount of flight time
/grant-flight <player> <amount> Gives a certain player, a certain amount of flight time
/remove-all-flight Removes all flight from all players
/remove-flight <player> <amount> Removes amount of flight time with a certain player
/tempfly <chat/actionbar> <enable/disable> Enables or disables chat messages or actionbar messages which displays flight time left, if active
/tempfly flight <enable/disable> Enables or disables temp flight
/tempfly-check Checks yourself for flight time left, or check's others by specifying a player