Air traffic throughout Europe this year has been plagued by delays, due in part to the war in Yugoslavia, a restructuring of airspace over France and Switzerland and problems with air traffic control in Italy, Greece and Spain. Now that the Yugoslavia conflict is winding down there’s hope for improvement, but a shortage of air traffic controllers may make things worse rather than better. Airports most severely affected are in Amsterdam, Geneva, Lisbon, Madrid, Milan, Munich, Oslo, Paris and Rome. Is the message for summer travel in Europe to take the train?