NEW DELHI/PARIS (Reuters) – Almost four years ago a handful of people gathered in Airbus sales chief John Leahy’s spacious country house outside Toulouse and argued long into the evening over curry and cigars. About $40 billion at catalogue prices, and the bill was for 430 jets, all sold to the same Indian airline — IndiGo, the low-cost carrier which has grown to become the country’s biggest airline in eight years of operating.