1. The liquids rule
In most countries, liquids, gels, aerosols, creams and pastes in carry-on luggage must be in containers of 100 ml or less, all fitting in one transparent resealable bag. The limit applies to the container size, not the amount left inside.
Check the exact rule at your departure and transfer airports: some countries still apply 100 ml limits on all flights, while newer scanners elsewhere relax them. Follow the stricter rule for the whole journey.
2. Electronics and chargers
Laptops, tablets, cameras and their chargers usually stay in carry-on luggage. Large electronics are screened separately in many airports, so keep them easy to reach instead of buried at the bottom of the bag.
Cables and chargers are generally fine in either carry-on or checked luggage, but check the destination country's rules for drones and other battery-powered devices.
3. Power banks and spare batteries
Spare lithium batteries and power banks are almost always restricted to carry-on luggage, with a typical limit of 100 Wh (or up to 160 Wh with airline approval). Devices containing built-in batteries usually follow the same rule.
Keep power banks with their terminals protected—ideally in their original packaging or with tape over the contacts—so they do not short-circuit in the bag.
4. What to keep accessible
Passport, boarding pass, liquids bag, large electronics and any medication you need during the flight should be easy to reach. Empty your pockets into your bag before the body scanner.
Medication, baby food and essential medical liquids are usually allowed in reasonable quantities, but declaring them at screening speeds things up.
5. Common mistakes
Common mistakes include carrying a nearly empty 300 ml bottle (the limit is the container), packing a power bank in checked luggage, and discovering a laptop at the bottom of the bag when the belt is already moving.
Another is assuming the rules are the same everywhere: liquid limits and electronics rules differ between regions and change with new scanners, so check both your departure and arrival airports.
6. Checklist before departure
Before departure: check the liquids rule at the departure and transfer airports; put liquids in one clear bag; keep laptops and tablets accessible; carry power banks in hand luggage with protected terminals; and keep documents and medication on top.