I need a round trip from Amsterdam to Prague. There are options on KLM (good because I'm a Delta flyer), Easyjet, or Czech Airlines. I'll likely be traveling with only a large backpack (it will fit in the overhead been of a 767). I'm wondering if I would be better off spending a little more for KLM and not stress about having to pay last minute for checking my backpack or if I should be ok with a backpack of that size. I don't know much about Czech Airlines but their prices are comparable to Easyjet. Any advice is appreciated.
*The backpack is a Kelty Redwing 50