The Australian CASA Safety Hub
Pilot safety hub | Civil Aviation Safety Authority (casa.gov.au)
The US FAA Aviation Handbooks & Manuals
Free US FAA publications, including the Pilot’s Handbook of Aeronautical Knowledge, the Aeronautical Information Manual (AIM) and the Federal Aviation Regulations (FAR).
Aviation Handbooks & Manuals | Federal Aviation Administration (faa.gov)
The Australian Aeronautical Information Package (AIP)
Aeronautical Information Package (AIP) – Airservices (airservicesaustralia.com)
Recreational Aviation Australia (RAAUS)
Recreational Aviation Australia (raaus.com.au)
Textbook: “Say Again, Please”
“Say Again, Please” by Bob Gardner is a comprehensive guide to aviation communication. It provides clear explanations and examples to help pilots improve their radio skills and ensure safe and effective communication in the air. It is available for free at archive.org:
Bob Gardner-Say Again Please.pdf (archive.org)
VATSIM
The largest online aviation network. Interact with over 100,000 other virtual pilots and air traffic controllers worldwide.