Dr Dorothy Gronwall documented how PCS subjects were sensitive to an altitude of 8,000 feet back in the 1970's. It cause a marked difference in memory and other cognitive abilities.

I have problem flying due to the over-stimulation. I need to sit up front and on the aisle so that I have minimal visual impacts. Otherwise, my brain gets overwhelmed with all of the seat backs and heads in front of me.

The standard cabin altitude in pressurized commercial aircraft is 8,000 feet. Unpressurized aircraft can fly as high as 12,000 feet or even 14,000 feet for short durations. Some island hoppers are unpressurized.