In the days of Wright Brothers, it would have been perfectly safe to take off and fly your airplane in any direction as long as you can see where you are, but i

In the days of Wright Brothers, it would have been perfectly safe to take off and fly your airplane in any direction as long as you can see where you are, but it's obviously no longer safe these days, and there are strict rules about where you are allowed and who you have to contact at which locations. "What is safe" obviously depends on who else are on the road.