buoyant

tending to float on a liquid or rise in air or gas

• “buoyant balloons”
• “buoyant balsawood boats”
• “a floaty scarf”

characterized by liveliness and light-heartedness

• “buoyant spirits”
• “his quick wit and chirpy humor”
• “looking bright and well and chirpy”
• “a perky little widow in her 70s”