Fixed in changeset/165300959 but there may be other buildings or features with the same problem.

This change duplicates some buildings. For example way/114928246

Done. Thanks.

Re-added the tag in changeset/121899161 as per discussion in changeset/117951762

How do I make free_flying:ground_handling a "valid" tag? It's already in sport=free%20flying?uselang=en-GB#Defining_the_practice_sites

The tag is mentioned here so I don't know why it was removed: sport=free%20flying?uselang=en-GB#Defining_the_practice_sites

You can find more information about ground handling here for example: https://flybubble.com/blog/improve-your-ground-handling