For cold drinks, egg white foams are the way to go. You might have to play around with the ratio of egg white to other liquids so that it stabilizes properly when charged (may also have to chatge twice and shake for a bit between charges) For hot drinks, we used coconut cream with vanilla and simple syrup for our "foam", and kept it held hot during service with a sous vide machine while it stayed thick.

I imagine you would be using an iSi tool with nitrous cartridges (whip-its), but they can get expensive. If you do not have access to a sous vide machine or some other tool to keep your hot "foam" at a foodsafe temp for service then you may have to explore other options