My personal favourite is Ryanair in Brussels airport. Ryanair generally use airstairs, and, as you say, often queueing outside. Brussels airport doesn't allow the use of airstairs. So Ryanair found a solution to be appropriately annoying; you get on the plane via a jet bridge... from an isolated building which has to be reached by bus, and which has no inside waiting space so you still have the opportunity to queue in the rain!

(In fairness, they don't _always_ do this at Brussels airport, sometimes using a normal jet bridge).