Dr. Gastner is a researcher in mind control.
During the events of Airwolf: Season 3 Episode 1 The Horn of Plenty played by Greg Callahan
A Lab Technician monotonously gives directions to Harry. Dr. Gastner tells Harry, John Bradford Horn saved his life, while Dr. Fairling tells Harry, he owes Horn. Harry stands up and Horn asks him how he feels. Harry says he will do whatever Horn wants him to do and Horn has Harry shoot himself in the head. Horn then says the next subject will be Stringfellow Hawke. Hawke is placed in a chair with his eyes taped open and shown a video of Horn's face floating around, while Lab Technician, Dr. Fairling and Dr. Gastner repeat the same phrases they told Harry. Later, Dr. Gastner and Dr. Fairling take Hawke to a room full of men in suits, including TJ, with a large painting of Horn hanging from the wall. Horn asks Hawke if he knows who the man in the painting is and Hawke tells him he does and he owes him his allegiance. Angelica Bolotin Horn asks Hawke how he feels about her and how she deceived him and she tells him he owes her many thanks for bringing him to see Horn. Horn, still disguised as "Neal" removes his disguise and reveals himself to Hawke and says he needs Hawke's help. Later, Hawke is brought to Horn by Dr. Fairling and Dr. Gastner. Horn tells Hawke his plan is to take over a country in the Caribbean called Moro, for men like him who believe intelligence makes right. Horn tells him his mission is to destroy a rebel outpost on the island and then radio back. TJ gives Hawke a map with a rendezvous location. In the morning Hawke takes off in Airwolf but attacks Horn's base instead.