A hot air balloon was featured in the very beginning of Ring Of Fire Part 1, and was flown by a marine biologist and his son. The red and white balloon was a generic lightbulb shape, but unusually, the red basket was made of metal, as were the sandbags.
Why the boy and his father were in the balloon at the time of a hectic storm is unknown, but their lives were nevertheless in danger. After a while of violently swaying in the wind, the balloon was eventually ripped away from the basket and destroyed. Thankfully, however, Thunderbird 2 arrived to pick up the boy moments before this could happen, and the falling father was saved before he could hit the ground.