Box office hits may slow in 2016 at Comcast ’s ( CMCSA ) NBCUniversal after a big run last year, but operating synergies between its film business and burgeoning theme park build-outs could be the gift that keeps on giving. Think Walt Disney ( DIS ), which a plucky Comcast tried to buy in 2004. Comcast instead pivoted and purchased all of NBC Universal from General Electric ( GE ) in 2011, getting cable TV networks, broadcaster NBC, a movie studio and two theme parks. Now a theme park rivalry is growing between Disney and NBCU as Comcast steps up investments in Florida and California and expands overseas as well. Comcast-NBCU in September acquired a 51% stake in Universal Studios Japan’s theme park in Osaka for $1.5 billion. It’s also building a $3.3 billion theme park in Beijing with local investors, slated to open in 2019. Comcast’s U.S. theme park attendance has climbed, owing to Orlando’s Wizarding World of Harry Potter and other projects. In 2015, Comcast’s theme park revenue jumped 27% to $3.34 billion, pro forma for the Japan deal, in Q4 rising 38.6% and topping $1 billion in a quarter for the first time. Operating income rose 42% to $1.17 billion. Excluding Japan, Q4 theme park revenue still rose 15.6%. “Theme parks must now be viewed as a foundational element of the Comcast story,” Craig Moffett, an analyst at MoffettNathanson, said in a research report. Harry Potter, Volcano Bay Coming This April, NBCU plans to open a Harry Potter attraction in Hollywood. In 2017, it’s slated to open up a water park, Volcano Bay, in Orlando, Fla. On Comcast’s Q4 earnings conference call this month, executives confirmed the acquisition of 475 acres of land, for $130 million, in Orlando, near an existing theme park. “We have a lot of land to work with,” noted NBCU CEO Stephen Burke on the call. Aside from expanding its theme parks, Comcast will likely build more hotels, a growing revenue source. While a U.S. recession could slow park attendance in any given year, Comcast’s theme park business is less tied to big events than is broadcaster NBC, which gets periodic lifts from the Olympics, Super Bowl and election-year advertising. New blockbuster movies, as well as older movies, provide grist for new attractions, since NBCU holds the intellectual property. Under Comcast, NBCU has added park attractions tied to its “Transformers” and “Fast & Furious” movies. More park attractions are on the way, analysts say, such as Reign of Kong and the Incredible Hulk Coaster. NBCU’s filmed entertainment revenue jumped 46% to $7.3 billion in 2105 thanks to the box office success of “Minions,” “Jurassic World,” “Furious 7” and “Fifty Shades of Grey.” The film unit’s operating income rose 75% to $1.21 billion. In 2016, NBCU has a weaker slate of films, analysts say, though new movies will come from its Focus Features unit, formerly USA Pictures. JPMorgan estimates film revenue will slide 33% in 2016, with operating cash flow also down. Reinvestments could spark a stronger 2017, when new releases will include the newest Mummy flick, “Mena,” as well as “Fast & Furious 8” and “Despicable Me 3,” according to BoxOfficeMojo.com. On Comcast’s earnings call, CEO Brian Roberts noted that the cable TV company has doubled the operating cash flow at NBCU since it took a controlling stake in 2009. Comcast’s free cash flow growth is lower than operating cash flow because it includes Comcast’s sizable investments in broadcaster NBC’s content, such as winning rights to broadcast the Olympics, plus theme parks. In 2015, NBCU capital spending rose 13.5% to $1.4 billion. Higher Ad Rates, Fewer Viewers For NBCU Comcast bought its controlling stake in NBCU close to the bottom of the advertising cycle. NBCU has been garnering higher ad rates. However, broadcasters and cable networks in general face falling audience ratings and a dropoff in pay-TV subscribers. NBCU’s cable networks — including USA, Syfy, Bravo, E! and CNBC – generated 70% of NBCU’s operating cash flow as of mid-2013. In 2015, the cable networks provided only 54.6% of OCF. “It’s hard to build a bullish story for Comcast’s mostly middle-of-the-road general entertainment networks,” said Moffett, though USA produced a hit in “Mr. Robot” in 2015. Theme parks churned out nearly 24% of OCF in 2015, up from 21% in 2014. Including Japan, theme park OCF could hit $2.2 billion in 2016. By 2020, theme park contribution to NBCU’s total OCF could rise to 35%, analysts say. Disney on Tuesday posted results for the December quarter, its fiscal Q1, and analysts say its theme park and resorts business performed well. U.S. park attendance rose 10%, with revenue growing 9.5% to $4.28 billion. Disney has been refreshing older attractions, such as Star Wars. In June, Disney is expected to open a park in Shanghai, its first in mainland China. In 2017, it’s slated to open an Avatar-themed park in Orlando. Like Comcast-NBCU, Disney seeks synergies between films and theme parks. “(With) Shanghai, Disney will have the opportunity to use the park to help exploit its considerable intellectual property portfolio, (and) the park may help open up the Chinese film market to more Disney releases in the future,” Omar Sheikh, a Credit Suisse analyst, said in a research report.