I let my child fly back and forth to see her grandparents starting when she was about that age. If any man had tried to touch her inappropriately the whole plane would have watched while she took her big heavy riding boots and jumped up and down on his face. No one messes with her, then or now.
LOL
My (then HS aged) daughter asked for some boots - we live in AK, makes sense.
She showed me the boots - German Tanker boots. OK, they are surplus and wear well. She insisted on the steel toed version - OK, safety first.
Where would she wear these - in a mosh pit of course. The young men learned very quickly about getting too close.
She does kick boxing as well. I know my grandkids are safe....