The USA Aircraft registration data and the USA pilot data are updated regularly from the FAA data.
The airport data for USA airports are updated regularly. Data for other airports are updated only very irregularly.
IMPORTANT: 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 airports, pilots and aircraft registrations.
Aviation related databases on guenther-eichhorn.com