Cheap homemade solution
I happened to have already some decent over-the-ear headphones. I also had on hand some foam earplugs.
Instructions: Insert earplugs. Wear headphones and crank up the volume to get past the earplugs.
Not sure about frequency response, but worked great on the last air trip when I had this setup. Also not sure how this might impact the people sitting next to me.
Biting the hand that feeds IT
