UK Flyer IDs and Operator IDs are not valid outside the UK.
You must always meet the national requirements of the country you're travelling to. Check with the applicable authority or regulator before you travel.
Flying in the EU
If you want to fly your drone or model aircraft in an EU member state, you'll usually need to register as an operator in that state. There are some exceptions, so you should always check with the relevant authority.
Taking your drone through an airport and on an aircraft
If you take your drone on a aircraft, you must carry any drone batteries in your hand luggage in separate LiPo-safe battery bags. We recommend discharging batteries to approximately 50%. You must follow the watt-hour limits set by the airline.
Never turn your drone or its controller on while you're travelling through an airport as this may activate the airport's drone detection alarms.
When you're travelling with the drone, after you've got off the flight, you might want to give it a check over physically make sure it's okay make sure there's no damage, please, whatever you do, don't actually turn your drone or controller on.
Most major airports these days have drone detection systems in place. And by turning the drone on, even if you're not going to fly in the airport terminal building will activate those alarms and that's not what we want.