The tail number is the aircraft registration number. Tail numbers are useful (among other things) for tracking private aircraft and non-scheduled charter flights. Typically these types of flights are not available in our system, which is optimized for regularly scheduled commercial passenger service. Commercial airlines may substitute a different operating aircraft equipment type for the scheduled equipment.
Cirium currently offers an API to retrieve the Flight Status by Tail Number:
If the aircraft tail number is provided by one of our data providers regarding a scheduled commercial flight, our system does pass this information along to our customers.