Certain airlines (e.g. Norwegian) do this. It's usually a more unpleasant experience because you can't use a jetway and have to use the stairs and be exposed to

Certain airlines (e.g. Norwegian) do this. It's usually a more unpleasant experience because you can't use a jetway and have to use the stairs and be exposed to the outside elements. Jumbo jets also often have multiple jetways (e.g. for the upper deck or the business vs. economy sections.