How can an helicopter end up with the same tail number than an airplane? For example, take N133AA.

https://www.jetphotos.com/registration/N133AA shows American Airlines photos from the 90s and an helicopter from this decade:



The FAA only shows the helicopter registry:


https://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=N133AA


Transtats shows that the last time N133AA flew from LA to NY was in 2008, and I'd bet that was not the helicopter.

Is it normal that tail numbers get reused? How can I make my cross-searches reliable?
N133AA appeared on an American Airlines DC10, but American Airlines retired, sold or scrapped all their DC10 and MD11 aircraft by 2002, releasing the registrations for other uses.

Wind the clock forward 15 years and somebody has used N133AA for a Robinson R44 helicopter. I speculate that the effective owner of the helicopter is one Agustin Anaya, who submitted the photographs to JetPhotos, even though the aircraft is registered to a company.

The FAA registry shows only the helicopter because the American Airlines usage was released long ago.