Currently, email is in a pretty standard state. It used to have that crazy spam concept… and now it’s just gone; but that doesn’t stop everyone else from spamming you!
There are two versions to this idea:
Simple date based deletion
All emails after a certain date get deleted automatically unless they are saved using the game’s existing save button. It currently does not do anything because all emails are saved infinitely regardless. The player can possibly be allowed to change the date before emails get deleted or disable the system altogether.
Flag based deletion
The game has an icon in the email UI with a red flag icon, currently, it does nothing! However, it could be used to mark emails as spam, which will be sent to the trash folder and deleted after a set time! If at anytime you want to start keeping the emails that are flagged, all you need to do is go into your trash folder and unflag one. This can allow players to easily filter out information they don’t want to know about and information they do.
Why would this benefit Airport CEO? After some buildup of emails (Depends on the PC, but mine started at about 100-200) the game can have a very serious lag problem when opening their email. This can be annoying when you have an email you actually want to read, and it takes up to 3 seconds just to open the darn inbox.