Airbus Group SE’s struggles with its A380 superjumbo are deepening as the planemaker delays deliveries of a dozen aircraft over the next two years to Emirates, the double-decker’s biggest buyer, potentially pushing the program into the red. Handovers of six A380s apiece originally planned for 2017 and 2018 will be shifted to a year later following an agreement between Emirates and engine supplier Rolls-Royce Holdings Plc, Airbus said Tuesday in an e-mailed statement.