Yes, put it and the batteries in your hand luggage. Then again, do you really want to check it and risk it being thrown about by the baggage handlers?
As Chris said - make sure the terminals are covered. Some airlines restrict you to no more than 2 batteries, so give a third one to someone else.
Some airlines also insist on fireproof bags for the batteries as well. Better to be safe than sorry. They are cheap as chips on Amazon, but if you want to borrow some - send me PM. I normally travel with mine at storage voltage as well, but I’ve never had to get the batteries out of my bag at any airport I’ve been through.
Enjoy! I don’t want to go to the area in high season, but this time of year it’s gorgeous, warmer than the UK, and pretty empty.
If you’re in the Portimao area and you have time, you might like to do the Seven Hanging Valleys Walk along the cliff tops. The coastline is simply stunning and almost perfect for a drone. I’m editing my footage this evening! The only thing that makes it not perfect - those bloody seagulls! Keep your eyes open & you’re fine.