Lets pretend that this is actually possible and AE could handle this, do you want to introuce airports in the year they are actually built?
For example, in 1998 Hong Kong closed its main airport at the time (Kai Tak) to make way for the new and current airport Hong Kong International Airport or Chek Lap Kok.
There are many examples of this, Bangkok, Don Mueang (DMK) and the new Suvarnabhumi Airport (BKK). Also Doha is an example Doha International Airport (DOH) and new Hamad International Airport (DOH).
This would mean that if the airport was completly closed, like Kai Tak and Doha, that the routes flown would have to be moved to the new airport. Also we would need to have a "Change Airport Origin" Button for the flights for the airports that didnt close but got down sized because of a new airport.
Lets just assume that this could be possible.