Perhaps some dark sunglasses or an eye mask if the light becomes bothersome, or a small flashlight or flashing keyring that you find visually appealing, something edible you enjoy (pre-packaged so you can take it on the plane). If you have a lightweight throw blanket or a sweater with a large hood, I find such things, when covering the head, act as a sort of barrier between me and the outside world. Perhaps some spinning or twisting fidged toys to keep your hands occupied, and a music player like an ipod with some songs you find comforting.
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"Survival is insufficient" - Seven of Nine
Diagnosed with ASD level 1 on the 10th of April, 2014
Rediagnosed with ASD level 2 on the 4th of May, 2019
Thanks to Olympiadis for my fantastic avatar!