The Hurricane Hunters are incredibly important to the accurate forecasts of hurricanes. The National Hurricane Center wrote this yesterday afternoon.
One of our readers asked me this question and while I thought I knew the answer, I wanted to be sure. So, I asked Dennis Felgen of the National Hurricane Center. His answer:
There is a lot of up and down and side to side pushing by the hurricane onto the aircraft (like being on a roller coaster in a car wash). If the aircraft were to fly over land during this turbulence it would have to deal with the structures on the land and the variable terrain itself. And that is too dangerous.