>satellites etc?
although not explicitely regulated internationally, the Karman Line at about 100 km (62 mi) is considered to be the boundary b/w atmosphere & space
"Airspace is the portion of the atmosphere controlled by a country above its territory"
Lowest short-term stable orbit for a satellite so far was 140 km (87 mi) for Lixing-1 for three days.
The Outer Space Treaty regulates that there can be no claim for sovereignty in space/orbit.