Museum Balloon Sweden
Thirty thousand passengers were carried in one balloon in five months and not a single flight lost due to bad weather! This helium balloon flew indoors in the Nordic Museum in Stockholm. The 9.5 m. envelope is enough to lift three or four passengers 10 metres in the air before a winch gently returns the balloon to its plinth. At times people queued for two hours to experience a flight.
For indoor ballooning using a real balloon like this, a large space is needed, although a smaller balloon could be used with winch assistance.