Why business jets fly highest
Most airliners cruise between 30,000 and 41,000 ft (FL300–FL410). Business jets such as the Gulfstream G650, Bombardier Global and Challenger 350 are certified to 45,000–51,000 ft. Up there the air is thin, fuel burn is lower, and they sit above airline traffic and most weather. Military aircraft such as the U-2 fly far higher, but they rarely broadcast. See altitude and flight levels.
Why “fastest” means ground speed
ADS-B reports ground speed, which is how fast the aircraft moves over the ground. That is airspeed plus or minus the wind. In winter the jet stream over the US can blow at 150–200 kt, so an eastbound 787 or A321 can show 650–700 kt over the ground while flying at a normal airspeed. Westbound flights fighting the same wind look slow. The speed chart above shows how airborne traffic spreads across ground-speed bands: the 400–499 kt band is mostly jets at cruise, and the slowest bands are helicopters, light aircraft and traffic near airports.
Why the highest aircraft is sometimes a balloon
Scientific and commercial stratospheric balloons can float at 60,000–120,000 ft with a transponder broadcasting, and they often top the altitude list while drifting at a few knots. They broadcast as emitter category B2 (lighter-than-air). Readings that are physically implausible for the aircraft type, such as an airliner at 70,000 ft, are filtered out of the rankings.
Climbs and descents
Vertical rate is reported in feet per minute. A typical airliner climbs at 1,500–3,000 fpm and descends at 1,000–2,500 fpm. Light jets just after takeoff and skydiving aircraft diving back to the airport can briefly show 5,000 fpm or more. Very large values for a single update are often data noise, so watch a few refreshes before you trust them.
For any record holder, tap through to airplanes.live to see its whole altitude and speed profile.