Lithium‑ion batteries power almost everything travellers rely on: phones, laptops, cameras, wireless earbuds and the power banks keeping them alive through long travel days. When these batteries overheat they can ignite, a chain reaction known as thermal runaway, which is why airlines have strict rules about where they are packed.
Most travellers are carrying several without thinking about it.
Your phone is now the boarding pass, the map, the camera, the translator and even the hotel key. A dead battery can quickly derail a travel day, which explains why portable chargers have become standard gear for many travellers.
But power banks are also lithium‑ion batteries, and packing them in the wrong place can at best mean unpacking your bag at the airport and at worst create a fire risk airlines work hard to prevent.
The one lithium‑ion battery rule travellers should remember
If an item contains a lithium‑ion battery, it should almost always travel in your carry‑on bag, not your checked luggage.
That applies to:
- power banks
- spare batteries
- most personal electronics
Airlines prefer lithium‑ion batteries in the cabin because crew can respond immediately if one overheats. In the cargo hold, problems are harder to detect and harder to contain.
Travel gadgets that contain lithium‑ion batteries
Many travellers underestimate how many batteries they are carrying.
Common examples include:
- phones
- laptops and tablets
- wireless earbuds and headphones
- smart watches and fitness trackers
- power banks and portable chargers
- cameras and spare camera batteries
- vapes and e‑cigarettes
- electric toothbrushes
- hair straighteners and heated styling tools
- portable fans or heated clothing
If it charges with a cable, there is a strong chance it runs on lithium‑ion.
The battery mistakes that cause airport delays
Airport staff report the same packing mistakes again and again.
- power banks packed inside checked luggage
- spare batteries loose inside bags
- vapes packed in suitcases
- oversized power banks without visible capacity labels
Power banks cause the most confusion. Travellers see them as simple chargers. Airlines classify them as spare batteries.
The lithium‑ion battery limits airlines use
Most airlines follow broadly similar limits.
- Under 100Wh – generally allowed in carry‑on
- 100Wh to 160Wh – may require airline approval
- Over 160Wh – usually prohibited on passenger aircraft
Many power banks list this as “Wh” or watt hours on the label.
If a battery appears swollen, damaged or recalled, it should not travel at all.
Can I charge my phone on the plane?
Increasingly, the answer is not always. A growing number of airlines have begun restricting or banning the use of power banks during flights due to safety concerns around lithium‑ion batteries.
That is important for travellers because many people now rely on their phones or tablets for most of their inflight entertainment. Instead of watching the seatback screen, passengers stream their own shows, watch downloaded movies, read, play games or catch up on work.
All of that drains batteries quickly. And when your phone also holds your boarding pass, arrival information, hotel bookings and ride‑share apps like Uber, running out of power before landing can become a real problem.
In some situations travellers may even be asked to power on their device during immigration checks. US border officers, for example, can request access to electronic devices, which means travellers need to be able to turn them on.
At the same time, not every aircraft offers at‑seat power or USB charging ports. Taken together, these factors mean travellers cannot assume they will be able to recharge their device in the air.
For many passengers the safest approach is simple: start the journey with devices fully charged.
If you do plan to charge devices during a flight:
- bring a charging cable in your carry‑on
- check whether your aircraft has USB or power outlets
KARRYON UNPACKS: Lithium‑ion batteries are now unavoidable in modern travel, but aviation safety rules are built around one reality: if a battery overheats, crew must be able to reach it quickly. That is why they belong in carry‑on, not checked luggage.
