Open Network and Sharing Centre ("Network Status" Win10).
Go to "Change Adapter Settings" ("Change adapter options" Win10)
Go to properties of Local Area Network (Ethernet).
Click on Internet Protocol version 4 and go to it's properties.
Click on Advanced
You will see a block checked there by the name of "Automatic Metric".
Uncheck it and then enter 2 in that section.
Now, do the exact same as above for the Wireless network but enter 1.
This will prioritise your WiFi over your LAN and also enable you to use your WiFi with your LAN still plugged in.