My eldest is aviation-obsessed. So naturally, he and his admiring siblings all want to see Walt Disney's (NYSE:DIS) next animated feature, Planes, when it opens on Aug. 9. Unfortunately for Disney stock investors, they might be in the minority.

Planes flies into theaters on Aug. 9. Source: Disney.

Percy Jackson: Sea of Monsters gets a two-day head start on Planes thanks to an Aug. 7 debut and is based on the popular children's book series of the same name. 21st Century Fox (NASDAQ:FOX) is distributing the film, just as it did its predecessor: 2010's Percy Jackson & The Olympians: The Lightning Thief.

Author Rick Riordan penned five Percy Jackson novels in all, each of which could be adapted into a film in the same way that Time Warner (NYSE:TWX.DL) adapted J.K. Rowling's Harry Potter books into one of the most successful film franchises of all time. Sea of Monsters is book two of Riordan's series.

Fox investors shouldn't expect Percy Jackson to reach Hogwartian heights. Yet it could be much worse: Google's Trends data paints a discouraging picture for those hoping Planes will be a catalyst for Disney stock:

Source: Google.

The message? Families are likely to spend more to see Percy Jackson slug it out with creatures of the deep than they will to see Pixar's airborne take on Cars. A shame, really, because the film looks entertaining:

Sources: YouTube, Disney/Pixar.

Of course, I could be wrong. Planes could still be as successful as Monsters University, the not-so-scary sequel to Pixar's Monsters, that has earned $578 million worldwide in a summer that's been good for animated films. Universal's Despicable Me 2 crushed The Lone Ranger at the box office while Fox's Epic earned $245 million worldwide on a $100 million production budget, Box Office Mojo reports. Among the major releases, only DreamWorks Animation's (NASDAQ:DWA) Turbo has failed to live up to expectations.

Now it's your turn to weigh in. Do you expect Planes to fly? What about Disney stock? Leave your predictions in the comments box below.