It would totally work, if the airhorn frequency was resonant with the vuvuzela length or one of its overtones. You could either alter the airhorn to match the vuvuzela, or the length of the vuvuzela to match the airhorn.

I demand an audio/video demonstration!

I don't think this could actually work….you need to blow it like a trumpet, not just force air into it. It's not a goddamn whistle..

I can already feel my ears bleeding.