The hot air balloon works on the principle of buoyancy, which means that when the balloon needs to fly higher, the air inside the balloon is heated so that it is lighter than the air outside. This means that the density on th inside is less.

if we assume that both are at the same temperature, then who will be sitting in the basket :). I mean you can't be there at that temperature in the first place. If the balloon is an automated one, then it will not rise in the first place as the weight of the canopy and the basket will keep the balloon on the ground.

Thanks