Green Lantern was originally scripted to stop a crashing plane instead of a train wreck, but this was changed after the terrorist attacks of 11 September 2001.
In the comics, Metamorpho was the first potential recruit to turn down Justice League membership. He would have been the fourth recruit, after Green Arrow, the Atom, and Hawkman.
Phil LaMarr and Danica McKellar also voiced Virgil Hawkins and Freida on "Static Shock". That series would include a crossover episode with Justice League.