In a Hijack scenario, you must steal a marked boat or car, which will usually be surrounded by several rival gang members. They can easily be picked off from afar with a Sniper Rifle, or you can drive right in and gun them down from inside your car.
Once you’ve killed the surrounding gang members, get in the vehicle and drive it to the drop off marked on your radar. You’ll likely be pursued by rival gang members on your way there. The drugs are in the vehicle, so you must remain in that vehicle. If the vehicle is destroyed, you’ll fail the job. This video is from our unofficial game guide. You can view the full guide here