Generally when majority of people travel, they travel during common travel times. Departure times tend to start as early as 5:00am and the last flight of the day often leaves around 10:00pm. I am guessing majority of you reading this have never considered IF the TSA Security Checkpoint would be open when you arrive at the airport, BUT you could be making a costly mistake!
For my example I will use my home airport of Chicago O’hare. On the FlyChicago website the TSA Checkpoint times range from 3:45am to 10:45pm for Terminals 1, 2, and 3. Terminal 5 (international terminal) is open 24 hours, but is not connected to Terminals 1-3. This means the main terminal at Chicago O’hare is effectively closed from 10:45pm to 3:45am each night. So, what happens if your flight leaves at midnight?
A friend of mine was flying on Frontier Airlines (yes, that was their first mistake) from Raleigh-Durham to Chicago and before they left for the airport they had been notified of a delayed departure. The flight would now leave Raleigh-Durham shortly after midnight. In an attempt to spend more time with family, they waited to go to the airport until 11pm. Sure TSA recommends you arrive 2 hours before your flight, but because it was so late in the evening, my friend assumed the security checkpoint lines would be short. They were correct, when they arrived to the airport the lines were short, in fact, there were no lines to speak of. Why? Because ALL TSA Security Checkpoints were closed for the night and they would be forced to miss their flight.
In this case, Frontier only flew to Chicago every other day, which meant my friend would not be able to fly back to Chicago (on their paid ticket) until 2 days following their oringal scheduled departure. In this case, it is the passengers fault for not being at the gate at the scheduled departure time and therefore the airline had no requirement to accommodate my friend.
I was unaware of this risk until I had heard the story from my friend. I was aware TSA PreCheck checkpoints close prior to or opened after general TSA Security Checkpoints, but had no idea that TSA Security Checkpoints closed entirely overnight. In the future if your flight is scheduled for a midnight or later departure it may be a good idea to check TSA Checkpoint times to make sure you will be able to access the boarding area.
Note: Airlines require passengers remain in the gate area during delays due to the possibly of an equipment swap. Occasionally a flight will be delayed only to leave hours before the new posted delayed departure time. Even if your flight is showing a late night departure it is good practice to be at the airport and in the gate area at your original scheduled departure time.