Federal Aviation Administration (FAA)
The National Flight Data Center (NFDC) web site makes available a part of the 56 Day NASR Subscription Files in AIXM 5.1 format. This includes airport, route, navaid and other data. The home page https://www.faa.gov/air_traffic/flight_info/aeronav/aero_data/ gives access to the data for the current data and also to past data sets.