Textron Aviation is betting that a boom in online commerce and package deliveries will provide a boost to the business aviation market’s nascent recovery—and it has found a valuable partner to hedge that bet.  In a surprise unveiling, the company has launched development of a twin-engine utility turboprop dubbed the SkyCourier 408, with service entry targeted for 2020. The announcement caps seven months of behind-the-scenes design coordination with FedEx, which becomes the ...