Flying isn’t getting any cheaper, and travelers who don’t book carefully may find that they’re paying more for a less comfortable experience.

Airlines have been adjusting their cabin configurations in recent months to fit more passengers, often resulting in a tighter squeeze for those in coach.

Earlier this month, JetBlue announced it had expanded legroom in new premium rows on some Embraer E190 aircraft—at the expense of an inch lost in the rearmost 11 rows. In January, Southwest began adding six seats to each plane, a change that also reduced legroom by an inch.