Originally Posted by stut
There are plenty airports that close, particularly those in urban areas. My regular airport, LCY, is even closed on Saturday afternoons (it's primarily a business airport and has not traffic at that time).
For some, it may be a simple question of demand, so you could have late night cargo flights. For others, it could be due to noise restrictions for the benefit residents in the flight path. Conversely, there are plenty 24-hour airports out there, too. LGW is an example, with the bleary-eyed charter pax checking in at some ungodly hour...
Ive done my share of overnight shifts at LGW and in the summer you would be amazed how busy it is. For example, immigration is busier at 2am than 2pm.
Fortunately some if the Costa Coffees stay open 24 hours. You can stay landside all night but most check ins dont open until between 4 and 5 am, this can lead to early morning security queues if all the desks open at the last minute. The North/South transit also runs every 6 minutes through the night.