@Wifiwits @TaylorSwiftsJets @simonzerafa
ADS-B transmissions are promiscuously broadcast by aircraft. Readily received, decoded, and plotted with an RTL-SDR device, a home made antenna & FOSS software.
Hence, Flughtradar24, Planefinder, and other tracker sites. To Swift’s annoyance, not all tracker sites implement ‘hide’ requests from operators.