There is missing or incorrect autogen scenery around my airport.
Ensure that you have the latest version of the applicable airport, which contains compatibility fixes. This is recommended for all Orbx airports starting with EG... (except EGJA-Alderney, which is not within the TrueEarth GB coverage area) and in particular, if you have TrueEarth GB South installed, where most Orbx addon airports are located:
Open Orbx Central, Go to My Products and select each airport individually. Click [Verify files]