What should an eco-conscious billionaire buy next: a pet or a jet? Patrick Hansen, the entirely unbiased chief executive of private aviation firm Luxaviation, is very clear: get the jet. At the FT’s Business of Luxury Summit in Monaco this week, Hansen cited one customer who produced a mere 2.1 tonnes of CO2 per year, which is the carbon footprint equivalent of three dogs. Plus, a jet won’t chew your shoes. Sorry, Fido.