I have used a yard-sale inflatable for the past two years as a placeholder for my pirate ship before putting it up. Worried the hell out of my fans - I had been telling people I wasn't sure whether the rotting wood had made it thru the winter behind the shed.
For those of you mentioning the storage issue - these things deflate and fit into a 12-inch square box. Easiest storage of all my props.
Last year I made a giant octopus inflatable who attacked the ship for Halloween weekend. It was easy and added to the fun.