Board Thread:General Discussion/@comment-178.202.244.251-20130106203239/@comment-1038387-20130117225821

Yep, there's plenty. It's easier to reuse old material; it shaves off the workload.

Couple more examples:
 * All police cruisers are the S:TAS/JL/JLU model.
 * The wide shot of the warehouse in "Downtime" was from (I think) the Fearsome Hand of Four scene in Batman: Under the Red Hood.
 * The Star City docks, and probably the Bludhaven docks as well, used backgrounds from the Gotham docks in Batman: Under the Red Hood.
 * After the Manta-Flyer submerges in the Metropolis docks in "Alienated", the background is the Gotham pier Supergirl crashed the Batboat into in Superman/Batman: Apocalypse.