my father won't let me buy those earmuffs. So I won't go.
Earmuffs are cheap and can be bought online. Maybe you can buy a pair on your own? But I understand that you are a student. If budget is an issue, please show this thread to your dad. You don't have to give up plane travel but you must take the necessary precautions. Tinnitus and especially hyperacusis are not well-known illnesses so we have to be our own advocates.
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We will be flying with the new A350 which is a quiet model. When we fly to Japan our seats are located on the 30 row. It is on the middle of the plane I think it will be loud but I will use earplugs and earmuffs the whole flight. 
