BERLIN/PARIS, Nov 18 (Reuters) - France, Germany and Spain have reached agreement on starting the next phase of development of a new fighter jet dubbed FCAS, Europe's largest defence project at an estimated cost of more than 100 billion euros($103.4 billion), the German government said on Friday.The ministry said it was agreed at the highest government level that a cooperative approach on an equal footing would be pursued in the project, which is under overall French responsibility.Lately, the project - originally meant to unify Europeans after the migration crisis and Britain's decision to leave the European Union - has been a source of tension between the two countries.Last month, Macron cancelled a joint Franco-German ministerial meeting over disagreements with Berlin on a wide range of issues including defence and energy projects.Other sources blamed Airbus for pushing for a bigger workshare of the Dassault-led project, insisting it should be given "equal footing" with the French company."