Actually in this case, it is actually based on a true story. The "inside the ship" aspect of the movie was absolutely nothing like what was actually reported, but the Travis Walton case did actually occur, at least in that a dude went missing for like a week and when he came back, he claimed he had been abducted by aliens.So no, the story behind "Fire in the Sky" wasn't created as a marketing ploy, but it was greatly embellished to make it more entertaining (if they had used the actual account of what he claims took place while he was on the ship, it would've been very dull indeed).