Southwest Airlines will introduce a new policy requiring portable chargers to be visible when they're in use onboard.

Southwest Airlines is implementing a new safety policy, effective May 28, requiring passengers to keep portable phone chargers and power banks visible during flights when you're charging a device. The airline will prohibit the use of these devices while they're stored in carry-on bags or overhead bins,

The TSA already bans rechargeable and non-rechargeable lithium batteries for phones and laptops from checked baggage. Carry-on baggage is fine, but Southwest Airlines will soon require those chargers to be outside of all bags and visible while in use during the duration of the flight.