An RF receiver is not required for the subject use case, they can use existing ADS-B IP feeds, process the feed (either live or with historical data) according to the 3D bounding box, and generate reports based on flight paths intersecting the bounding box.
Airloom – 3D Flight Tracker - https://news.ycombinator.com/item?id=46080289 - November 2025 (106 comments)