Winds and wind direction are generally layered in different altitudes. The pilot ascends or descends until he or she finds a wind going in the correct direction. The pilot has close control over altitude and the rate of ascent or decent by regulating the burner and vents. Most balloons have a parachute valve at the top to release hot air, which can be opened by pulling a valve line. Once hot air is released, the balloon will descend.
Inflation begins when cold air is pushed into the balloon envelope with a portable blower .
When the envelope is almost inflated, the burner is ignited and the air is heated until the balloon becomes buoyant. Hot-air balloons usually cruise at an altitude of 3,500 feet. Many balloon flights occur between 50 and 1,000 feet above the ground. But balloons can fly at treetop level or go much higher. The world record for altitude in a hot air balloon is 64,997 feet.