You've downloaded a local plate for the airfield so SkyDemon overlays it on the map thinking you want to see what's in it, when you're within the area it covers. You can:
1. Press the red cross in the corner of the plate to hide it, when it appears
2. Delete the plate you've downloaded, if you don't actually need it, then SkyDemon won't show it
3. Turn off the option to automatically show georeferenced plates on the maps, which I think is in Navigation Options