LUXEMBOURG (Reuters) – EU finance ministers agreed on Saturday on a voluntary levy on airline tickets to fund extra development aid but there was confusion about how it would work. «This will be a voluntary contribution which some member states propose to turn into a mandatory contribution but we are leaving this open,» said Luxembourg Prime Minister Jean-Claude Juncker, who chaired talks by 25 European Union finance ministers. Five or six countries were ready to go ahead, he added. Officials said the accord was embryonic but the basic idea was that each country could decide whether to apply such a tax. Payment might also be voluntary for air travelers. At least some countries openly voiced objections. Austrian Finance Minister Karl-Heinz Grasser attacked the scheme as a burden on consumers and a distortion of competition. Greece, objected too. «We do not support it. It would penalize regions of the EU that are geographically disadvantaged… It would not be a good way to raise revenue to help developing countries,» Economy Minister Giorgos Alogoskoufis told reporters.