The next LEGO film to open will be the as-yet-untitled LEGO Batman™ feature, which is coming to theatres earlier than planned, with the global launch starting domestically on February 10, 2017. Seven months later comes “Ninjago,” which had been slated for release in fall 2016; however the film is still under construction so it is being moved to September 22, 2017 domestically, with international dates to follow. “The LEGO Movie Sequel,” the follow-up to the smash hit “The LEGO Movie,” is opening one week earlier than originally slated, now being released domestically on May 18, 2018. ...
It's gotten way more regimented at movie studios since they all went corporate.
Once upon a time (the 1970s? The 1980s?) cartoon producers wouldn't lock an animated feature to a release date. They wanted to be the movie would be completed (and hopefully as good as they could make it), THEN they would book theaters.
That all changed in the go-go nineties; truth to tell it was changing in fits and starts before then.
Earlier, when Richard M. Nixon was President, there didn't need to be a hard and fast release date because there were only a few hundred prints foisted on the general public at any given time. The first Rescuers, for instance, had three or four hundred prints in circulation, and it had to share release patterns with Herbie Goes to Monte Carlo. Herbie got rolled out on the eastern side of the country while The Rescuers was released in the western half of the U.S.
The "four hundred print release" is now as dated as a bowl haircut. Today if you don't have 1500+ theaters showing your movie, your an art house picture that's getting a limited rollout. Studios are now cogs in the exhibition-distribution-marketing machines known as entertainment conglomerates, and none of the big boys are in the business for anything other than maximum profit.
That means scheduling your tent pole years in advance, way before it gets made. Then the production crew grinds away, with a deadline etched into stainless steel staring everybody in the face. Sometimes dates get moved, but not often. Usually people get to work twelve hour days six or seven times during the week. And resign themselves to seeing their kids on the other end of the production pipeline.