Anything Flammable
One more reason to choose natural fabrics! And cover your arms, legs and feet in case the unforeseen happens and you have to go down the emergency slide. A long-sleeved cotton t-shirt is breathable as well as protective.
High Heels, Backless Sandals, Flipflops
They make it difficult to quickly evacuate the aircraft, and could hurt others if they go flying off. Heels could puncture the evacuation slide and they’ll sure make it a lot harder to run to another gate if necessary.
Meanwhile, that tiny airplane bathroom is even nastier if something on the floor gets on your toes. ‘Nuff said. Opt for closed shoes such as sneakers, low heels or flats, or boots.