I tend not to wear jeans on the plane -- even the most comfortable jeans are a bit too constricting on the plane, ime. I travel in comfortable slacks -- St. John is my go-to brand, whether their knitwear, if I am going straight to a more business type event when I get off the flight, or their various versions of leggings. I have two pairs that are a cross between leggings and slacks (essentially, they pull up, like leggings, but are thicker, and not totally skintight, so fit more like slacks). I can pair them up with a sweater or dress them up with a tank and a jacket.