The USA airplane data are downloaded from the FAA regularly.
Disclaimer: None of the data can be used for flight, they are for non-critical personal information only. Do not rely on these data in any way. The FAA is the primary authority as to the "real" information for all information regarding USA airplane registration data.
The search for an N-number will return one entry if it succeeds.
Search Form for N-Numbers on www.guenther-eichhorn.com