When Chas and John are in the car being chased by demon dogs, Chas asks John if he can "magic them away". John answers: "Who the hell do you think I am? Benedict bloody Cumberbatch?" No doubt a reference to Cumberbatch's character Stephen Strange in the Marvel movie Doctor Strange. Strange is an accomplished sorcerer.
Matt Ryan, the voice of Constantine, has played the character in live action in the TV shows Legends of Tomorrow and the short-lived Constantine series, as well as guesting as the character on the CW's Arrow.
When John is opening all the doors to hell and threatening Nergal he asks for help and Constantine-like demons appear. The first one to appear exclaims: "Here's Johnny!" A reference to Stanley Kubrick's 1980 "The Shining".
The Los Angeles Daily News at the airport is written in Latin.
The twelfth Installment Of The DC Animated Movie Universe