Jackson, MS (KJAN) hasn't had a curfew in effect for 10 years now.. http://www.gcr1.com/5010WEB/airport.cfm?Site=JAN&CFID=8347263&CFTOKEN=65986763
Why is it still showing in AirwaySim?
Same problem at KSAN. Take off curfew is 2300. But planes can land 24/7. This has not been corrected in sim for a few years. Lived there a lot of my life and very close to KSAN (like 2 miles) under the approach pattern. Big jets landed there many times during middle of the night. America West at 0230 from KLAS, cargo planes and the biggest of all was a DL L1011 from HNL at 0430. So I know what you're talking about. Frustrating. :-\
Reason is, that there is no way to split curfews into landing/starting or cargo/passenger times yet.
Hopefully some day eh?