Amsterdam Airport Schiphol is the main hub for KLM (one of the world’s oldest airlines and serves over 150 destinations) and one of the busiest airports in Europe. But how much time does one need to connect through Amsterdam Schiphol? Exactly how long depends on a number of factors (including if it is an international or domestic transfer), but one should allow for at least an hour. According to OAG, Amsterdam Airport is the third-busiest international airport in the world when measured by seats (with around 3.4 million seats monthly).