This child’s idea is brilliant. After the plane does a water landing or ditching I can see this child’s vision of leaving a trail of balloons in the water and stones at the bottom. Maybe include RFID’s on each balloon with the airplane’s registration number.

http://www.foxnews.com/travel/2015/11/20/delta-executives-consider-8-year-olds-idea-to-improve-plane-safety/#.VlGeMg_mseM.gmail