Question: Which American superhero action-adventure television series developed by Ali Adler, Greg Berlanti, and Andrew Kreisberg stars American actress Calista Flockhart?

Context paragraphs:
The Flash (2014 TV series): The Flash is an American television series developed by Greg Berlanti, Andrew Kreisberg and Geoff Johns, airing on The CW.  It is based on the DC Comics character Barry Allen / Flash, a costumed superhero crime-fighter with the power to move at superhuman speeds.  It is a spin-off from "Arrow", existing in the same fictional universe.  The series follows Allen, portrayed by Grant Gustin, a crime scene investigator who gains super-human speed, which he uses to fight criminals, including others who have also gained superhuman abilities.

Supergirl (TV series): Supergirl is an American superhero action-adventure television series developed by Ali Adler, Greg Berlanti and Andrew Kreisberg (the latter two having previously created "Arrow" and "The Flash") that originally aired on CBS and premiered on October 26, 2015.  It is based on the DC Comics character Supergirl, created by Otto Binder and Al Plastino, and stars Melissa Benoist in the title role.  Supergirl is a costumed superheroine who is Superman's cousin and one of the last surviving Kryptonians.

Calista Flockhart: Calista Kay Flockhart (born November 11, 1964) is an American actress best known for playing the title character in "Ally McBeal".  She is also known for her roles in "Brothers & Sisters" and "Supergirl".  She has been featured in a number of films including "The Birdcage" and "A Midsummer Night's Dream."

List of Supergirl episodes: "Supergirl" is an American superhero action-adventure drama television series developed by Ali Adler, Greg Berlanti and Andrew Kreisberg (the latter two having previously created "Arrow" and "The Flash") that originally aired on CBS and premiered on October 26, 2015.  It is based on the DC Comics character Supergirl (Kara Zor-El), created by Otto Binder and Al Plastino, and stars Melissa Benoist in the title role.  Supergirl is a costumed superheroine who is the biological cousin to Superman and one of the last surviving Kryptonians.

List of Legends of Tomorrow episodes: "Legends of Tomorrow" is an American action-adventure television series developed by Greg Berlanti, Marc Guggenheim, Andrew Kreisberg and Phil Klemmer, who are also executive producers along with Sarah Schechter and Chris Fedak; Klemmer serves as showrunner.  The series airs on The CW and is a spin-off from "Arrow" and "The Flash", existing in the same fictional universe.

Pilot (Supergirl): The pilot episode of the television series "Supergirl" premiered on CBS on October 26, 2015.  It was written by series developers/creators Greg Berlanti, Ali Adler and Andrew Kreisberg, and directed by Glen Winter.

List of Supergirl characters: "Supergirl" is an American television series developed by Greg Berlanti, Ali Adler, and Andrew Kreisberg based on the characters created by Jerry Siegel and Joe Shuster in the "Superman" franchise and Al Plastino and Otto Binder's character Supergirl (Kara Zor-El).  The series stars Melissa Benoist in the titular role of Kara Zor-El / Kara Danvers / Supergirl, as well as Mehcad Brooks, Chyler Leigh, Jeremy Jordan, David Harewood, and Calista Flockhart, with Chris Wood, and Floriana Lima joining in later seasons.  In addition to original characters, several other characters from DC Comics universe also appear throughout the series.  For its first season, "Supergirl" aired on CBS, before moving to The CW for its second season.

Legends of Tomorrow: DC's Legends of Tomorrow, or simply Legends of Tomorrow, is an American superhero action-adventure television series developed by Greg Berlanti, Marc Guggenheim, Andrew Kreisberg, and Phil Klemmer, who are also executive producers along with Sarah Schechter and Chris Fedak; Klemmer and Fedak serve as showrunners.  The series, based on the characters of DC Comics, airs on The CW and is a spin-off from "Arrow" and "The Flash", existing in the same fictional universe.  The series premiered on January 21, 2016.  In January 2017, The CW renewed the series for a third season, which is scheduled to debut on October 10, 2017.

Arrow (TV series): Arrow is an American superhero television series developed by writer/producers Greg Berlanti, Marc Guggenheim, and Andrew Kreisberg.  It is based on the DC Comics character Green Arrow, a costumed crime-fighter created by Mort Weisinger and George Papp.  It premiered in North America on The CW on October 10, 2012, with international broadcasting taking place in late 2012.  Primarily filmed in Vancouver, British Columbia, Canada, the series follows billionaire playboy Oliver Queen (Stephen Amell), who, five years after being stranded on a hostile island, returns home to fight crime and corruption as a secret vigilante whose weapon of choice is a bow and arrow.

Stronger Together (Supergirl): "Stronger Together" is the second episode in the first season of the CBS television series "Supergirl", which aired on November 2, 2015.  It was written by series developers/creators Greg Berlanti, Ali Adler and Andrew Kreisberg, and directed by Glen Winter.

Supporting paragraphs: Calista Flockhart Supergirl (TV series)
Answer: Supergirl