"Dr. Gastner is a character who makes a one-time appearance in the Season 3 episode titled The Horn of Plenty (episode).
Dr. Gastner is one of the doctors specialising in mind control drugs and technques employed by the villainous tycoon John Bradford Horn. When Hawke is captured by Horn's troops, Gastner and Dr. Fairling work on Hawke to brainwash him and program him into thinking that he owes his life and allegiance to Horn.
It is not known if Gastner survived Airwolf's subsequent attack on the base. It is likely that Archangel would have sent in reinforcements to mop up the place and he might have been arrested by them if he had survived.
Dr. Gastner is played by Greg Callahan in what appears to be his first acting credit.