Reminder: This plugin is still not production-ready, so use it at your own risk.

Changelog:

• Added a new setting "max-time" in config.yml for defining the max time a player can accumulate to fly with an elytra. By default is 600s (10min)
  
• Fixed a colour bug on the shop and effects GUI items
• Improved flight time handling in boos bar, adjusting automatically depending on the amount of seconds (similar to the formated time placeholder)
• Fixed a bug where the players could boost infinitely, gaining an absurd amount of speed.
• Added the option to remove the sound when boosting.

My next priority will be to add automatic recovery, where flight time will be restored automatically over a specified period. This is already implemented in the config.yml, as you can see, but it doesn't have any effect.