The seats are often bigger bc they RF until 4-5 and even 6 years old in Norway. And, out of Norway they will usually deny you using a car seat on the plane just bc they don't really allow it.
And a bucket is the only thing you would be allowed to bring in, one which can be installed with a lap belt. But, as I said, they wont allow you usually anyway out of Norway. They say it's safer without the car seat, and that the safest is to have the kids on the adults lap with the belt you get.
The point is--airlines seem to disagree on what is safe and what isn't...US based airlines say car seats are safer, while most European airlines (aside from some...like German ones) seem to advocate for the belly belt.
So my question is--why can't they come up with some kind of airline provided seating for babies and toddlers...like the ones they now have on British Airways in the bulkhead? Internationally, there seems to be so much disagreement on car seats...and surely it would be better for the airlines to provide seating rather than rely on parents to bring a suitable seat. Though, I guess if most international airlines say belly belts are safer, it becomes a moot point...