This seems like it would be common sense information for anyone flying on an airplane, but with the 4th of July coming up the FAA wants to remind people that under no circumstances should any type of fireworks be brought onto a commercial airliner.
(FAA) "Fireworks, including even the smallest sparklers, can pose a tremendous fire risk to aircraft both in the air and on the ground. They are not permitted aboard the aircraft. That means they cannot be stored in carry-on or checked bags and they cannot be brought on the plane in a passenger's pockets."
Source: Planet Data