"Destroy the fourth target" is an objective in the mission Bomb Drop 1 in Grand Theft Auto V
Walkthrough[edit]
If you are after completing things quickly, do not follow the Great Ocean Highway. The quickest way is to just head straight for the target. Climb to get over the mountains and head right for your target. There is no altitude restriction: use it. You should be able to spot the smoke for the final drop location while going through Braddock Pass. Line up as you approach. There are a lot of trees in the which means you need to drop from a little height at least.
Once the drop is made, it is time to head back to the airport. Just climb on over the mountains from there and land on the airstrip from the east.
