A CBS News analysis of the FAA's data found that since 2021 there's been at least one lithium battery incident on a passenger plane somewhere in the US, on average, once every week.

Some airlines are taking action to control the growing number of fires. They use specialised "thermal containment" bags designed for flight crews to use if a lithium battery starts heating up to the point where it's smoking or burning.

Mechanical engineers at the University of Texas at Austin say the bags can effectively contain fire and keep it from spreading, but don't extinguish it.

An engineering professor at the university's Fire Research Group even showed a lithium-ion battery fire that continued burning underwater. "You can't put it out. It's a fire within the cell. So, you've got fuel, oxygen, heat in the cell, all."

Guidelines from America's Federal Aviation Administration require spare lithium-ion batteries be kept with passengers (and not checked) — and prohibit passengers from bringing onboard damaged or recalled batteries and battery-powered devices. It does not say if airline staff have ever checked if passenger phones have been damaged or recalled.