I worked for US airlines for 8 years, and now for a British Airline. The US is ALL seniority.... You bid for everything, and could end up on straight reserve every month until your seniority can hold anything decent. Long haul takes years...... Decades! On the plus side they have none of the "Briefings" like in the UK with answering questions etc, and the Flight Benefits are very good (unlimited, free, best class available in most cases) For women going on maternity, the USA is terrible. Pay is pretty much the same -- if not worse in the USA since 9-11.