Geneva, July 27, 2007. Swiss airspace is one of the most complex in all Europe, and the air traffic controllers of skyguide are among the most productive. Skyguide controlled almost 6% more aeroplanes in the first half of 2007. This figure equates to almost 600,000 instrumental flight rules (IFR) flights. However, delays also increased. The average delay per flight is 1.91 minutes, and this is due not only to the weather but also to the politically imposed procedures in the Zurich region.