Some missions are time-based meaning if you don't complete certain tasks in time, you will fail them.
If you feel the time ran out quicker than expected, please provide us with a detailed ticket to help us determine the issue.
NOTE: The only mission with a timed feature is Mission 2 - Reach for the Skies. You have 10 minutes to reach the hurricane and then an additional 10 minutes to land after finding the hurricane.