The planning and a lot of the design work for an A220-500 has been done. From a sales standpoint, Airbus is limited in their 320 family throughout. Their backlog goes out years and will continue to do so. An a321 costs only a little more to make than an a320, but the price and resultant margin is a lot higher. In other words, Airbus would rather sell a higher priced 321 than 320. If another production line can “eat into” A320 sales, they are still selling a plane in the 160 seat area and freeing up a higher margin 321 production slot, and in theory contributing to the a220 economy of scale needed to bring that program into profitability. They are focusing on ramping up the a220 production, and once that ramp is complete and production costs lowered, I’d expect the -500 to launch. I don’t think Airbus cares about losing future 320 sales—they need the 220 program to get profitable, and they need to optimize production and maximize sales to do that. There’s also supposedly a higher thrust engine (just a PiP for the current engine) coming out in the next few years for the 220 family that will give the -300 better short field performance, and will presumably be used (or maybe just be an option) on the -500.