"The thing that we didn't really plan on -- again because we weren't aware that we were going to switch Supergirl from CBS to The CW and it was really going to be part of it -- that was the one show that actually didn't have built-in shutdown days, so all the other ones did," he continued. Because the show starts on Supergirl, Melissa [Benoist] ended up being heavily in The Flash and then in Arrow.