The cruise industry is benefiting from strong demand and increased booking volumes. Solid bookings concerning North American and European sailings are driving the space. Also, strong pricing (on closer-in-demand) and solid onboard spending bode well for the industry.At this stage, it will be prudent to invest in cruise line operators with a favorable Zacks Rank. A few such operators have strong upside left. Three among them are Royal Caribbean Cruises Ltd. (RCL) , Carnival Corp. & plc (CCL) and Norwegian Cr ...