In 2002, an episode of the animated series Justice League based on the DC Comics superhero team of the same name, titled "Legends" aired. It featured four members of the team being sent to an alternate universe and meeting the Justice Guild of America, a parody of the Justice Society of America, the League's precursor in the comics. However, they originally intended to outright feature the JSA but had licensing issues. A short promo was released featuring the JSA, instead of the JGA featuring brief completed animation and voice acting.
Based on the fact that this was even released, the episode must have been pretty far into production when they had to swap the Society for the Guild.
It was several more years before Jay Garrick appeared in animated form. Even then (before the JSA's own episodes), it was only in the Brave & Bold opening teaser segment, and for some reason, he wasn't named, either as Jay or Flash!