From Bulbapedia, the community-driven Pokémon encyclopedia.
The Pokémon Balloon Race getting started
The Pokémon Balloon Race is a competition held in Johto, featured in The Big Balloon Blow-Up.
Trainers ride in hot-air balloons shaped like various Pokémon. They can use Flying-type Pokémon to steer, and Fire-type Pokémon for hot-air. The balloons must first ascend to 1000 feet up in the air and race towards a target on the ground. They then must drop a weight and try to land as close to the X on the target as possible. The prize for the winner is brand new hot air equipment.