Potentially serious disruptions are expected in French air space and at airports starting from Tuesday, as air traffic controllers go on strike to protest European Union reforms being implemented in their sector, airline and air traffic sources confirmed on Monday. The strike is to begin Tuesday morning and run until Friday morning. Paris airport officials at Aeroport de Paris (ADP) said they were asking airlines to cut back on flights by as much as 50 percent depending on the route. Delays and cancellations at both Paris airports can be expected and also at regional airports. Roissy-Charles de Gaulle Aiport in Paris is the second busiest in Europe; any disruptions there would have a significant rippling effect on other nations\' air traffic. However, it is also expected that several other European air traffic controllers\' unions, in Hungary, Belgium, Slovakia, Portugal, Austria and Czech Republic, to call for industrial action in the coming days. This could exacerbate international traffic Europe-wide and beyond.