The reason that the 5GHz WiFi band is disabled during flight (airplane) mode is comply with local regulations. There are regions in the world where the usage of the 5GHz band is not allowed to be used for WiFi transmissions. As the Lumia WP8 phones are unable to determine the location whilst in flight mode, the phones disable the usage of the 5GHz WiFi band in order to comply with regulations.
- What to check if I can't sign in or create the Microsoft account on my Lumia phone during the initial setup?
- What is the WhatsApp messenger and where can I download it?
- How do I switch my Lumia calendar views between 12- and 24-time format?
- How do I remove my Lumia phone from the account settings at windowsphone.com?
- Why don't I have the option to select a non-Bing hardware search provider?