What did Carlson expect would happen if the turkeys had been able to fly? The helicopter was so high that Nessman could not tell what they were at first. Likely they would have flown away, leaving onlookers baffled. (Wild turkeys can fly, somewhat, but presumably WKRP had domestic ones.)
ETA: Carlson wasn't the brightest bulb, and probably did not think it through, but he likely had some image in mind.