production.ERROR: Attempt to read property "code" on null
This does not mean that the "code" is missing, contrary to what you think the main object is missing. And in this particular case it is an "airline" (hint is checking the line number provided in error details). How to debug this error is explained in Most Common Errors topic with a similar example.
So in theory, checking and/or editing airports will not solve this, updating to latest dev and latest Dispo addons will not solve this either... Most probably this is a pirep with a broken/missing airline, it can be a flight too, as both have direct relationship to airlines.
Disposable Basic offers a simple database check page, in which admins can see some risky records with their id's, it does NOT fix stuff but helps identifying the errors quickly. It can be used to figure out which pirep/flight is causing trouble.
Also if this is the same problem discussed in discord, the error was caused by another 3rd party module which was messing up pirep records and directly recording stuff to v7's database etc.
Hope this reply helps people in future
Good luck to all