ADS-B Exchange is a must nowadays to keep track of any interesting aircraft passing by. Years ago it was unimaginable to be able to do this - and even more on your cellphone! When I had the opportunity I made some 600mm photographs of some of the most interesting aircraft passing by. Sometimes the serial numbers could be read of the photograph; most of the times the aircraft were noted on airbases coming from of travelling to by spotters and posted on forums/ facebook. Or the aircraft were common to be flying around a certain period to acknowledge their serial numbers.
C5M 87-0040 crossing in opposite direction of KC135 62-3542. These are very common travelling between CONUS/ UK (Mildenhall) and Germany (Ramstein/ Spangdahlem) or further eastbound - but rarely caught on 1 photograph!
The same Beluga XL A330, F-GXLH, seen around 12:00 crossing North East towards the Airbus Hamburg facility and 3 hours later back again towards the South South West.
The Steadfast Noon 2022 exercise had several aircraft flying from Kleine Brogel (Belgium), Volkel (Holland) and Spangdahlem (Germany) flying missions towards the North Sea. On the 26th of September the Kleine Brogel mission aircraft could all be seen flying towards the South on RTB. These consisted of 3 USAF Lakenheath F15E Strike Eagles, 2 Luftwaffe Tornadoes and a total of 6 Belgium F16's. All flew around FL240.
Above the two-ship Jackall 01 and 02 (91-0329/LN and 96-0204/LN)
All aircraft were spotted with call signs and serial numbers on Kleine Brogel and posted on forums and fb. Beneath two Belgian F16's (Detox and Conan flights).
During, to and from airshows military aircraft (fighters) normally are visible on ADSB. As can be seen on some of the departing aircraft on the 18th of July 2022 which attended the RIAT at Fairford: