Is "Fight or Flight" distance genetic
It probably is somewhat genetic.  A good example is pigeons.  When you approach them, they turn their back to you so that if you get close enough they can escape / fly away.  I'd be surprised if this is only a learned behavior, but I also note that pigeons who have been fed let you approach to a closer distance than other birds, so in this example a distance is not completely hard wired.  

Such behaviors are more likely a combination of learned and genetic, especially as the animal becomes more complex (has a larger brain).  This is a major concern of 'ethology'. 

I think few inherited behaviors are completely inflexible.