Yeah i have the same airmon issue the last few days. The fix for it is this "iw dev wlan0 interface add mon0 type monitor"
That's assuming you want "wlan0" in monitor mode. It's only a band-aid tho. I have to do it every time i reboot or swap wifi cards. I don't remember if i read that fix here or on another forum/blog. I've been troubleshootin a ton of stuff with not much sleep past few days. I remember somebody mentioning they thought it was caused by kismet tho. Nethunter's doing the same thing tho.
I don't know how to make it persistent, but i'm sure there's an easy enough way to do it. That command is just adding a monitor interface called mon0 to wlan0 so airmon will create mon0 instead of wlan0mon. Dunno why it doesn't stick across reboots. Never needed the iw config files before. But there's gotta be an equivalent of /etc/network/interfaces for iwconfig somewhere in /etc or /usr.
