It also cleverly maxes out on easyJet's dimensions so not an inch of precious underseat space is wasted. Underseat luggage FAQs, answered:What counts as underseat luggage? Also called a personal item, underseat luggage is any piece of hand luggage that fits underneath the aeroplane seat in front of you. After using each multiple times, I reviewed each against the following criteria:Materials & durability Is the underseat luggage of good quality, hard-wearing and fit for purpose? In terms of my personal experience with luggage, I don't travel light and so rarely rely on underseat luggage alone.