That reads like you're not doing it on your own network to me.
If you are on your own network: there is no reason for driftnet to operate any differently to if you are wired or not - you may need to route traffic through your device (or make it act as a WAP), but the basic principles are the same. Make sure you've actually connected to the network rather than just sitting there sniffing it.
It works just fine on my WPA2 network.



