Hannover Airport has struggled to generate increased demand in recent years, possibly due to a reluctance or inability to attract Europe's low-cost carriers to serve the airport. New routes from network carriers to their hubs were opened and closed after one season/year due to low demand (e.g., Aer Lingus, Air Baltic, TAP Air Portugal). Although traffic grew satisfactorily during the late 1990s, during the last decade there has been little growth. In both 2007 and 2008, traffic was down less than 1%, but in 2009 it fell by almost 12%. Hannover Airport is one of very few German airports which are open 24 hours a day, but there are very few flights between 23:00 and 04:00.