4J

• 4J Studios
• Douglas A-4 Skyhawk
• Eugene School District 4J
• J4 (disambiguation)
• List of McDonnell Douglas F-4 Phantom II variants
• McDonnell Douglas F-4 Phantom II
• McDonnell Douglas F-4 Phantom II non-U.S. operators
• Piper J-3
• Somon Air
• The Android Invasion
• Wyoming Highway 50