Tom Stubbs tells Johnny that he needs his uncle dead in order to give him a better chance of being elected. He needs it to look like a terrorist attack though.
After seeing Mr. Stubbs penis, Johnny will appear outside with a Rocket launcher. You'll be told to get to the airport runway in roughly 15 minutes (real time). Once you're near the airport, you'll get a text from Stubbs telling you that you can either take out the helicopter as it lands, or wait until his uncle is in a car and destroy it in convoy. If you get locked into the airport, he has a guy who can help you.
As you approach the GPS marked location, you'll be told by the cops to go away. I personally think the best way to tackle this is to head all the way to the North of the airport runway along side the large grey concrete wall and then around the back of it into the airport. Park your bike near the large gas containers and fire an RPG at the car in the middle. If you got there quickly enough, you should be able to kill the target with your first shot.
Now you need to get to the other end of the airport, to the unlocked gate. I suggest sticking to the runway for this as it will give you more space to move around and dodge the cop cars which will be swarming all around you.
Get to the gate, speed through it then follow the road pretty much straight ahead. Make a left into the tunnel and once you get outside the wanted radius and wait for a few seconds, you'll be rewarded.
- Completely ignore entering the airport through the usual gates. The best point of entry is to go all of the way around the walls to the North.
- Fire a shot from the RPG at the middle car just as the target is about to enter.
- Stick to the runway when making your escape.
- Stock up on armour before attempting this mission.
- You really want to take out the target from distance, or you'll get brutally gunned down by the many cops.
From the Lost club house steal a bike, car, etc. and go to the helipad
near Niko's Alderney safe house and grab the HELICOPTER/chopper.
Enter and head out.
Go to Stubbs' location and park the chopper in the street.
Leave the chopper door open.
Enter the marker, and skip the video. Head to the airport.
Ignore all messages or incoming calls.
Land on the hangar nearest the arriving chopper.
Ignore the warning about cops.
Aim your RPG at the arriving chopper.
Keep firing until the "target is dead" message appears.
If you fired before he landed, he is dead.
Otherwise, use a sniper, etc. to take out Stubbs' uncle.
You should have no health or armor damage.
Leave the area in the chopper until you are out of the wanted radius.
Once you are clear of wanted level, you will immediately get a phone call
to do a mission helping Ashley. Using the same chopper you're in now,
can help get in and out of there fast.