When you're going on holiday, the rules surrounding hand luggage can be difficult to figure out.
But there is one specific rule that isn't very commonly known, and could get you banned from your flight if you don't follow it.
Since Covid restrictions relaxed and more people have been able to go on holiday, luggage reclaim has been a major issue.
Many people have been left waiting hours for their bags as staff struggle to keep up with the demand, so some have taken to attach tracking devices such as Apple AirTags to their belongings.
But the Mirror reports that devices of this nature could actually mean your bag isn't allowed on the flight.
Earlier this week, airline Lufthansa warned that it was "banning activated AirTags from luggage as they are classified as dangerous and need to be turned off".
This brought a furious response and then a prompt U-turn from the German carrier, which later told The Mirror that it had "conducted its own risk assessment with the result that tracking devices with very low battery and transmission power in checked luggage do not pose a safety risk".
Under current regulations, lithium batteries contained in the portable electronic devices, such as locating devices, should be taken as carry-on baggage rather than placed in the hold.
Other airlines such as easyJet, TUI, Ryanair and more have differing policies about smart luggage that holidaymakers are being urged to check before they set off.
Lufthansa's statement posed further questions, such as whether tracking devices with high battery power were also risky, what current regulations are and which body sets them.
Heathrow Airport and the UK Department of Transport denied being responsible for setting the rules, while a spokesperson for the CAA said it just enforces ICAO Technical Instructions.
Luggage with location devices are only allowed in the hold if they are protected enough that they won't be accidentally damaged.
They also must be fully turned off rather than just in "sleep or hibernation mode". This rule means AirTags and other trackers are effectively banned from being checked-in on all commercial flights in the UK as they won't work without being turned on.
Lithium batteries can cause problems on planes as they have potential to short circuit, sparking very hot fires that cannot be extinguished.
It's for this reason that aviation authorities also have strict rules around smart bags, which have charging banks and locks powered by batteries.
Recently, journalist and podcaster Pandora Sykes claimed she was not allowed to board an easyJet flight with her smart bag.
They said: "Beware anyone being so foolish to fly easyJet - captain just refused to let us board our flights because our checked-in suitcases have USB ports (aka “smart bags”).
"EasyJet quietly changed their Ts&Cs a few weeks ago without telling their customers."
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