Where the data comes from. adsb.lol publishes every day's full trace of every aircraft its volunteer receivers heard (one fix every few seconds). We keep the aircraft its registry marks as military. Finished days come from that history; today comes from our own sweep of adsb.lol's military list every 2 minutes plus the regions people are watching, so today is coarser and a leg can be missing its start or end.

Legs, hubs and corridors. A leg starts where the trace flags a new leg or after a gap of more than 30 minutes. A leg's end counts at an airfield (civil or military, from OurAirports) when it is on the ground or below 3 000 ft within 10 km of it; otherwise it is "first or last seen near" a place and counts nowhere. A hub is any airfield with at least one military arrival or departure that day. A corridor is an origin and destination pair where both ends matched, per class. Lines are great circles between the two fields, not the track flown.

Normal and surges. Normal is the median of the previous 28 days on record, or of the previous four same weekdays when there are four and they differ from the 28-day median by more than 30 %. With fewer than 14 days on record there is no normal and no surge. A surge is at least 4 movements and at least twice normal and at least normal + 3. "About 1 day in N" is how often a count this high would come up by chance if the normal held (Poisson).

What we can't see. Only aircraft that transmit ADS-B or are multilaterated by community receivers; many military flights transmit nothing or turn transponders off. Coverage is thin over the oceans, Russia, China and much of Africa, so an empty corridor there means unseen, not unused. Classes come from the type code; aircraft with no type are counted as type unknown. This page counts movements and compares them with normal. It says nothing about why aircraft fly, and it is not an intelligence product.