Northern Blue may refer to:

• Plebejus idas, a butterfly
• Transdev Northern Blue, former bus operator in England

• List of the busiest airports in Austria
• List of the busiest airports in Barbados
• List of the busiest airports in Belgium
• List of the busiest airports in Belize
• List of the busiest airports in Bosnia and Herzegovina
• List of the busiest airports in California
• List of the busiest airports in Ceuta
• List of the busiest airports in Chile
• List of the busiest airports in China
• List of the busiest airports in China (2000-2009)
• List of the busiest airports in Colombia
• List of the busiest airports in Corsica
• List of the busiest airports in Costa Rica
• List of the busiest airports in Croatia
• List of the busiest airports in Denmark
• List of the busiest airports in Ecuador
• List of the busiest airports in El Salvador
• List of the busiest airports in England
• List of the busiest airports in Estonia
• List of the busiest airports in Finland
• List of the busiest airports in French Guiana
• List of the busiest airports in Germany
• List of the busiest airports in Gibraltar
• List of the busiest airports in Greece
• List of the busiest airports in Guatemala