Ed Yost own interests turned toward reviving the lost practice of manned hot-air ballooning. This technology had first been invented in France by in the late 18th century by pioneers led by the Montgolfier brothers, but under the Montgolfier system, the balloon's air was heated by a ground fire prior to the balloon being released. The inherent danger of this type of balloon flight led to the system being abandoned when hydrogen and later helium became available. One of Yost's key engineering insights was that a hot-air balloon could be made to carry its own fuel. The invention of relatively light burners
Hot air balloon kingdom, during the Three Kingdoms era (220–280 AD), used airborne lanterns for military signaling. These lanterns are known as Chinese lanterns (). In the 18th century the Portuguese Jesuit priest Bartolomeu de Gusmão envisioned an aerial apparatus called "Passarola" which was the predecessor of the hot air balloon. The purpose of "Passarola" was to serve as air vessel in order to facilitate communication and as a strategical device. In 1709 John V of Portugal decided to fund Bartolomeu de Gusmão's project following a petition made by the jesuit priest and an unmanned demonstration was performed at Casa da India in