There's no single "hot wire" for the radio in a 1997 Ford Aerostar. The wiring color codes vary depending on the specific radio and the vehicle's options. You'll need to consult a wiring diagram specific to your Aerostar's year and trim level. A Haynes or Chilton repair manual for your vehicle is your best bet. These manuals will have detailed wiring diagrams showing the color codes for the power and other radio connections.
Trying to determine the hot wire by color alone is risky and could damage your vehicle's electrical system. Using a multimeter to test for power is a much safer way to identify the correct wires.
