Greed Corp
12 Achievements
200
Fear of Flying
You defeated the enemy without going airborne
20
How to unlock the Fear of Flying achievement in Greed Corp - Definitive Guide
The CPU AI will usually place harvesters such that you soon end up on islands with nothing but the cannons you started with. You too should place the harvesters in your territory to do the same.
Of note, you are allowed to build a carrier, or win one from an enemy, so long as you do NOT use it. I find it helpful to build a carrier as it changes the AI strategy to be a little more defensive - they won't leave their islands undefended if they believe you are going to fly over.
Sooner than later, all the AI will be stucked in just one island, probably not very well defended. Keep building ammo to punish the strongest AI in each turn, and keep building soldiers so the enemy can´t invade you without leaving his island undefended or losing almost all soldiers.
Each AI will build many planes (in my play each one had 3 planes) but none of them will atack you. They will try to destroy the other players (as they are weaker), so they get their funds and planes. After some time, they will kill themselves using harvester, until there´s only one AI island. When that starts to happen, you will have many spots with 16 soldiers and a bullet every turn, so the AI won´t be able to fight you. Keep firing with your cannon and you will win.
I found it funny how I won an expert match by only losing 5 soldiers with a cannon. Being always stronger than them will net you easily a victory without using any plane.
This must be done in the Empire campaign, which takes place between levels 19-24.
The fact that you're unable to use carriers, means you are going to need to build cannons. Build at least two, with a focus on buying shells each turn. There is an element of luck involved, as ideally, you want the enemy to focus on taking out the other enemies. To try and deter your opponents from attacking you, create two armories and buy walkers. You want 16 for each armory and 8 or more on a third tile. If you can eliminate an opponent, do it. The added funds and (possibly) a carrier will be a great help. You can own carriers, but are not allowed to use them. Owning carriers makes the computer reluctant to attack you.
Continue to buy shells and pick off any enemies when they're down to their last tiles. When it is just you and one other opponent, bombard them! The achievement will unlock upon winning the match.
Note: Level 19 (Morana Base) is the best map for this achievement.