If you want to go hot air ballooning, it requires the transport of large quantities of gas in cylinders, which is pretty energy-inefficient and also dangerous.
Today’s invention is a way to balloon in hot countries.
A large, plastic fresnel lens focusses the sun onto a ceramic tile of the type used on the space shuttle. This will transfer a large amount of heat to the surrounding airflow, without significantly heating the basket to which it’s attached.
The air in the envelope is thus gradually heated enough to allow takeoff to occur (with a small gas bottle and burner on hand in case of long periods of overcast weather).