Suspect Neil Entwistle appears to have returned from England in the FAA Gulfstream IV with tail number N1. The flight route was Gatwick(EGKK) - Bangor(KBGR) - Bedford(KBED).
This is probably a blocked flight but entering tail number N1 returns an “Invalid” error. Another FAA aircraft N12 can be tracked.
Many of the FAA aircraft (such as N11, N12, N15) are available and not blocked in the NBAA or FAA block lists.
We haven’t seen any information in our feed about N1 - N9, so they may be blocked at the FAA level or not included in our feed for other reasons.
Our web interface was marking it invalid but our database back-end and tracking engine are agnostic about what’s in the flight identification field and would not be confused or drop the flight.