Norwegian's checked baggage policy mentions that travelers with children and infants may check a car seat or stroller free. They also recommend putting your stroller in a Stokke PramPack to avoid damage.
Since this costs more than a typical Norwegian ticket, if your stroller isn't gigantic and folds to 56 x 46 x 25, a more obvious thing to do is bring it as a carry-on. The hand baggage policy doesn't mention whether a folding stroller will be allowed as a (not extra) carry-on.
Does anybody have experience with this?