The series expired on March 30th.
A search of Netflix no longer yields results for any DC shows (or movies) related to: Batman, Superman, Wonder Woman, Green Lantern or Justice League.
Likewise, search results return nothing for the Cartoon Network series: Regular Show, Adventure Time, Generator Rex, MAD, Codename Kids Next Door, and Cow and Chicken.
Select Cartoon Network series are still available including: Ben 10, Billy and Mandy, Chowder, Dexter's Laboratory, Johnny Bravo, Samurai Jack, Foster's Home For Imaginary Friends, Ed, Ed N Eddy, Cow and Chicken, and Power Puff Girls.
Some of the available Cartoon Network series now list April 6th as their expiration date.
The expired DC animated series include: Justice League Unlimited, Justice League (2001), Young Justice, Batman Beyond, Green Lantern: The Animated Series, and Batman: The Brave and The Bold.
We previously reached out to Warner Bros. about the expirations, but never received a reply back.