Look up a US-registered aircraft by tail number (N-number, e.g. N757F) or icao24 Mode-S hex (e.g. aa3487). Pass exactly one of `tail` or `icao24`. Returns the airframe: registration, manufacturer, model, ICAO type code + class, serial number, operator, owner, build year, engines, category, plus the icao24 Mode-S address that ADS-B transponders broadcast — use it to join live flight-tracking feeds. ~307k US airframes. 404 if no match. Source: OpenSky Network aircraft database (CC-BY-SA).