Airlines have quietly changed the rules on something that sits in nearly every traveler’s bag. The consequences of showing up uninformed range from a frantic scramble at the gate to missing a flight entirely.
Power banks have earned their place as a travel essential. Long layovers, packed terminals, and marathon flights are hard on devices, and a dead phone at the wrong moment can derail an entire trip.
But a sharp rise in in-flight battery incidents has pushed America’s biggest carriers to tighten their policies, and those changes are already being enforced at gates across the country.
The Numbers Are Hard to Ignore
The scale of the problem surprises most people who hear it for the first time. According to data from UL Standards and Engagement, an average of two flights per week experienced a thermal runaway incident in 2024.
Thermal runaway is what happens when a lithium battery overheats beyond control, triggering a chain reaction that can escalate from smoke to open flame within seconds inside an aircraft cabin. It is as serious as it sounds.
Vapes were the leading cause of these incidents last year, accounting for 28 percent of all reported cases.
Power banks, though, are the fastest-growing concern, with a 42 percent year-over-year increase in reported risk. One in five incidents in 2024 caused a major disruption, from diverted landings to full passenger evacuations.
What the Major Airlines Are Now Enforcing
The specifics vary by carrier, but the direction is consistent: lithium batteries must stay within watt-hour limits and remain accessible during the flight.
American Airlines began enforcing new rules on May 1, capping passengers at two portable chargers with a maximum of 100 watt-hours each. Devices must stay within easy reach during the flight rather than buried in a bag.
United Airlines rolled out its updated policy on March 1, asking passengers to keep portable chargers and vapes out of overhead bins entirely. The airline reached out to customers directly before the change took effect and also introduced restrictions on lithium-ion battery size.
Southwest Airlines has moved to a one power bank limit per customer, capped at 100 watt-hours, with the requirement that it remain in the cabin rather than stowed overhead.
Delta Air Lines has introduced its own size limits on lithium batteries, with parameters that differ somewhat from those of the other major carriers.
The Federal Aviation Administration advises passengers to alert flight crew immediately if any lithium battery or device begins overheating, swelling, smoking, or burning.
Crew members are trained to handle these situations, but early notification significantly changes how the incident plays out.
What Actually Makes a Power Bank Risky
Not every power bank carries the same level of danger, and knowing what drives the risk makes it easier to assess what’s in the bag.
David Wroth, senior director of technology and systems at ULSE, points to power density as the core issue.
Higher-capacity power banks store more energy, and more stored energy means a more serious incident if something goes wrong. Smaller, lower-capacity chargers carry less risk for the straightforward reason that there is less fuel available.
Physical condition is the other major factor. A power bank that has been dropped repeatedly, crammed into tight bags, or compressed over years of travel is far more likely to fail than one that has been handled with care.
Travelers who have owned their charger for a long time should take a close look before the next trip.
The warning signs worth knowing include visible swelling of the casing, unusual warmth during or after charging, and any unfamiliar odor. A swollen power bank should not be packed under any circumstances.
Where the charger was purchased matters, too. Products certified to recognized safety standards carry measurably lower risk than uncertified alternatives, which tend to show up at steep discounts through online marketplaces. The savings rarely justify the tradeoff.
What to Do Before the Next Flight
Before heading to the airport, confirm that the power bank falls within the watt-hour limit set by the specific airline being flown, since the policies are not identical across carriers.
Most standard consumer models come in under the 100 watt-hour threshold, but higher-capacity chargers marketed to outdoor adventurers or remote workers may not.
Keeping the charger in a readily accessible spot, such as a personal item or jacket pocket, satisfies both the safety intent and the new airline requirements. Placing it in a checked bag is not permitted under any of the updated policies.
For travelers who habitually pick up cheap chargers at airport kiosks or from unfamiliar sellers online, now is a reasonable time to switch to a certified product from a reputable brand. The price difference is usually modest, and the risk reduction is real.