Don't let the headline fool you, Barry Allen is still set to first appear in episodes 8 and 9 of Arrow, but now Grant Gustin will first be seen as The Flash in his own pilot.
Initially the plan was to have The Flash appear in costume during episode 20 of Arrow as a "backdoor" pilot, but studio executives decided to go with a full standalone pilot after reviewing episodes 8 and 9 of Arrow which have already been shot and are said to have been well received.
Deadline reported on the news with mention it is unknown if The Flash will still appear in that episode 20 of Arrow.
This is definitely good news because if The Flash is getting a pilot, that just about means his own TV series is a definite go. It's also reported that The Flash will still have ties to the Arrow universe as Grant Gustin appears in episodes of that series.
The Barry Allen episode of Arrow is set to air in a couple weeks with the CW already having released the episode synopsis:
Season 2 Episode 8 "The Scientist" Synopsis:
BARRY ALLEN COMES TO STARLING CITY — A seemingly impossible robbery at Queen Consolidated’s Applied Sciences Division brings Central City police scientist Barry Allen (guest star Grant Gustin) to town. Citing a similar case back home, Barry offers to help Oliver (Stephen Amell) and team with the investigation. Oliver senses there is more to Barry than meets the eye, but he’s distracted by the similarities between this current case and something that happened on the island. Meanwhile, Felicity (Emily Bett Rickards) takes a liking to Barry, which doesn’t go unnoticed by Oliver. Sin (guest star Bex Taylor-Klaus) asks Roy (Colton Haynes) for help when a friend of hers goes missing. Roy is surprised when Thea (Willa Holland) not only encourages him to help, but joins the search. Unfortunately, Sin’s friend is connected to Brother Blood (guest star Kevin Alejandro), and their search ultimately gets one of them seriously injured. Michael Schultz directed the episode with story by Greg Berlanti & Andrew Kresiberg and teleplay by Andrew Kreisberg & Geoff Johns (#208).
Arrow airs Wednesdays at 8pm ET on the CW.