It doesn't stay off for me either, but after some digging on the internet, Wingman appears to be an in-flight wifi network on planes (which may not actually exist anymore and T-Mobile are in the process of removing from devices according to this recent comment by a stranger on an old Reddit thread[1]). While it's annoying that it doesn't stay off, it doesn't seem to be something that would cause problems in practice because flights typically only have one wifi network.
