First time flying Air Canada this summer, got a great deal flying Shannon to Toronto in tango, but I'm just wondering seen as its a 737 8Max is it worth paying the 42 Euro (65 Cad) for preferred seating. Also the outbound is currently pretty empty so if i didn't pay for a seat is there a chance a preferred seat would becoming cheaper or free, also premium economy is empty and economy to premium pricing is roughly 200 more, would air Canada offer an upgrade at check in and if so is it usually very expensive if empty. Thanks