The European Union has approved the use of cellular phones to make calls during flight. The EU has been investigating in-flight calls for six months, and this approval means that the first services could launch as early as next month. The EU Telecom Commissioner sternly warned mobile operators to keep pricing reasonable, and asked that airline operators make sure those with phones do not disturb those without. The EU has also approved a set of rules so that in-flight use of mobile phones is safe. Last year, the FAA put the idea of making phone calls from airplanes on indefinite hold in the U.S. Americans who travel overseas to countries that permit in-flight calling should check with their carrier about potential fees.