hot-air balloon

:  a nonporous bag of light material that can be inflated especially with air or gas: such as

:  a bag that is filled with heated air or a gas lighter than air so as to rise and float in the atmosphere and that usually carries a suspended load (such as a gondola with passengers)

:  an inflatable bag (as of rubber or plastic) usually used as a toy or for decoration

:  relating to, resembling, or suggesting a balloon

:  having or being a final installment that is much larger than preceding ones in a term or installment note

:  to swell or puff out :  expand

:  to ascend or travel in or as if in a balloon

:  to increase rapidly