I remember watching this episode when the first aired in 1979, and I was at age 13 fascinated with WW1 planes at that time, so it was naturally a big hit with me then.
Rewatching it again for the first time in 43 years, I still enjoyed it, especially since now I am familiar with Don Adams, having seen reruns of Get Smart and his other routines Many times in the last 40 years.
The Red Baron episode is of course my favorite among the two stories - Adams plays a locksmith from Milwaukee who is a World War 1 history buff. His fantasy is to do battle in the sky with the Baron. Adams is playing a somewhat toned down version of his Maxwell Smart character. He's more intelligent, less clumsy (but still a bit of a klutz) and there are a few serious moments, especially at the very end - I won't spoil it, but he makes a very poignant decision. The plot is a "behind enemy lines, steal the battle plans" caper. The French woman he becomes attached to is played by Martine Beswick, who appeared in two James Bond movies in the 60's. Nice tight plot with humor added in, overall still one of my favorite stories in the series.
The flipside story is a love story, a woman who is in her 50's wants to be young again and find romance. She does, and while I found the likable little love story predictable, it played out nicely and was well acted.
At this point the series was in full stride, and I used to very much enjoy my childhood Saturday nights at 10 pm watching episodes like this one.