What is the third airport near Dubai visible on Google Maps?
The airport is Al Minhad Air Base:


  Al Minhad Air Base is a military installation in the United Arab Emirates. The base is located approximately 15 miles (24 km) south of Dubai and is operated by the United Arab Emirates Air Force. It is currently the headquarters of Joint Task Force 633 and supports Australian operations in the Middle East.




If you turn on Google Earth view, you can see the single road leading into the airbase from the east: