|Why would you want flight mode on a PC. Flight Mode is something you find on portable devices like smart phones and tablet computers. It has no use unless you are planning on setting up your PC on an aircraft.|
Even if there were flight mode, before any one can help you we need some information on model numbers. I could tell you how to find flight mode on my Android Tablet but it wouldn't be much use to you unless you also have an Android Tablet.
So some information on your wireless router and you PC would take out the guesswork.