Missed the airfield

Have you tried looking in the showcase as that's a good place to start. 1000s of ideas in there.
Here's a post with some ideas https://forums.ea.com/en/the-simpsons-tapped-out/discussion/91198/whydw-world-event-stuff/p1

The future proofed home and (kinda) the food needle from Krusty Land make passible control towers. I like using modern mansion pieces from SH for a terminal and you can build a nice runway just with pavement tiles and clever use of crosswalks for runway markings.

You can also go old school with a dirt runway and a simple, non-descript building as a “terminal.” I used a row of brown houses crammed together and windows hidden by trees for my first airport before we got the actual event. Not ideal but I at least felt like I had an airport.

You could also go on google images and type tapped out airport as there's lots of ideas there.

yeah I found that one, but all the airport thingies in there have items I can't get anymore

Many of us had home brew airports before the world traveler event. So do some image searches as suggested, and you'll likely find more of the stuff we posted before we rebuilt during the event. As mentioned above, there's lots of other features we repurposed to simulate airport buildings. You can certainly make a good one. I had a large runway made simply from road surface, before i added to it with the event's runway pieces. Go check it out and update us with what you build! ?