Weaponized 10 vehicles
After the seventh story mission, you’ll gain the ability to Weaponize vehicles. Approach any military vehicle such as an APC and mash X/Square to Weaponize it.
Completed a //BLACKNET mission
You’re forced to do at least one //BLACKNET mission early in the story’s progression, so this achievement is automatic.
Meet Father Guerra
This is also a story-related achievement that you will automatically unlock early on.
Destroyed 10 Blackwatch tanks, APCs or helicopters using a single hijacked tank or APC
We prefer starting at the Green Zone Blackwatch base with the helipad. Hijack one of the tanks, then immediately destroy all of the other vehicles in the vicinity, including the inevitable strike team. If this isn’t enough, drive out of the base and head north. You’ll encounter more hostile vehicles on the way and have this achievement in no time.
If you want to do this anywhere else, hijack a vehicle and simply cruise around the city, destroying any hostile vehicles that you encounter. It might just take a bit longer than our above method, but it gets the job done. Note that you cannot hijack until you finish the Yellow Zone story missions.
Destroyed 5 helicopters using Pack Leader
Once you’ve unlocked the Pack Leader ability (story mission 16B: Alpha Wolf, Green Zone), use it to summon your Brawlers, then target a helicopter (triggering a strike team is a quick way to find them) with left trigger and click the right stick. The Brawlers will either leap at the chopper or throw concrete at it. Repeat 5 times for the achievement.
So Above it All
Spend at least 25 consecutive seconds in the air (helicopters don’t count)
Helicopters may not count, but you can certainly jump out of one. An alternative is to leap off of the Empire State Building in the Red Zone. As long as your movement abilities are decently upgraded, you should have no trouble unlocking this achievements using either of the above methods.