Additional Authorised Contributors
In the future I plan to add the facility for others to further develop airports that have been started by someone else. This would be a little like GitHub's forking concept where the original still exists but modified/enhanced versions also exist. Until then as a quick stopgap I have created a new option called Contributor, whereby someone can be given permission by the author to have edit access to a particular airport they created. Please bear in mind that quite naturally not everyone will be willing to do this as they may worry about someone making mistakes and losing work or having different opinions about how to model things. For airports that have had very little development though and the original author does not wish to spend more time working on it they may give you access. Just please don't be upset if someone says "sorry, i'd rather not, I will do more work myself later". If you want to ask for contributor access to an airport that has been created already, please send the Author a request via private conversation.
You can see when someone else is authorised to edit - a Contributor line is shown in the airport overview as in this example below. KJKsimmer gave Oldar edit access (well actually Kenneth gave me permission to do this one on his behalf).
How Authors may give someone else Contributor Access
Just go into edit your airport as normal and you'll see a new field to enter the IPACS ID of anyone you want to give contributor access to. Hit save and you're done. You can always remove them at a later date if you wish.