Hi @mceldir, thank for writing in. I found this blog which might be helpful. Airports have a lot of parent/children polygon, and if they are fully enclosed they don’t include foot traffic. (I don’t know if this is the reason for your specific example, but it’s a guess!)
"Children that are enclosed (enclosed == True) are basically not distinguished from their parents. They do not have their own separate foot traffic data. Sometimes they have their own polygons, but sometimes they’re just a part of the parent polygon, although they may have their own latitude/longitude data.
Children that are not enclosed (enclosed == False) have parents but also act as independent locations. We track visitor data like visits_per_day separately for those locations, and they have their own polygon data in the polygon_wkt column."