from Homestead, F-16s could intercept something around Palm Beach within 4-5 minutes from take off.
still seems too far away.
wherever POTUS regularly hangs out, there should be at least a few apache gunships stationed within 1-2 minutes to provide air cover and shoot down capability if needed.
I live about 45 miles north of West Palm Beach.
When the President is in the area we have a whole passel of fighter jets and helicopter gun ships flying the area keeping an eye on things.