Complex sentence: Flight crew is to report to the airport at 2040 (8:40 pm), which means the crew will have to arrive earlier to park, clear airport security, and get to their operations office to check in.
Split into simpler sentences: Flight crew is to report to the airport at 2040 (8:40pm). Which means the crew will have to arrive earlier to park, clear airport security, and get to their operations office to check in.