I have installed kali linux on virtual box and when I hit the airomn-ng then, no driver found error pops up. Google suggests tobuy suitable wifi adapter. I tried TP-link WN722N. It did not worked. Any solution? Please!
If you are not in possession of your WiFi adapter & if you have run iwconfig without WiFi adapter ever hooked to Guest, then above is what you shall anyways get.
Generally speaking Kali & Backtrack both should support WN721 & 722N.
Try connecting any pen drive and check if it's recognized by the Guest.
If VirtualBox is not recognizing any of the USB Devices at all, just in case, then you may have an altogether different problem. Also do check out this thread if you are using Windows as Host and this thread if you are using Linux as Host.
I have personally successfully used both Kali & Backtrack on Windows Host + VMWare Player (Free for non commercial use) Guest with WN721N. If you are using Windows you can give it a try with VMWare Player. It has however very limited USB 3.0 support though. Only a select USB 3.0 chips are supported.