All flare guns and flares are restricted from carry-on luggage, but they can go in your checked-in luggage.
A flare contains explosives that if discharged on board a plane would present as a significant risk to passengers and crew.
You will be asked to relinquish all dangerous goods and weapons found in your luggage, carried contrary to the restrictions. If you refuse:
You will be asked to relinquish all dangerous or prohibited items found in your carry-on luggage. If you refuse:
AvSec X-ray bags going onto aircraft to ensure there is nothing dangerous in them.
For more information, see Retrieving your removed items.