limited flight time for differ categories

[siulung201314]

Players can get reward after playing every cooldown period. However, the flight time is cumulative without upper limit. It would be nice to have different upper limit of flight time for different categories.

For example, normal players can have 1 hours flight time reward after every cooldown period. The upper limit of flight time for normal players is 1 hour. If they have 59mins flight time already, the flight time can be only increased to be 1 hour after a cooldown period.