Ground vehicles are AI controlled mobile ground units which vary in mobility, armor and weaponry. They are used as operation objectives and optional targets with XP and Lion rewards on nearly all maps within the game.
Ground vehicles come in three distinctive groups, Light, Medium, and Heavy, which relate to the armament required to kill them.
Light variants require very little firepower to kill, as they have little to no armor. Machine guns and cannons of any description can easily kill a light target, so long as they hit the target. Bombs are equally effective as 50kg+ bombs will one hit these targets.
Light vehicles are most common around the lower tiers as most countries lack the armament to kill anything tougher. However they still can be found in higher tier battles. These vehicles include armored cars and mobile AAA.
Medium vehicles require more damage to kill than light targets. Unlike the light variant, they cannot be damaged by default machine gun or cannon fire, needing the ground targets ammunition type equipped to inflict damage on the target. Bombs 100lb+ will guarantee a kill (if it lands close enough to the target). This type of vehicle can be found from lower tiers up to high ranking battles. This class is made up of medium tanks.
Heavy Vehicles 
Heavy vehicles require the most amount of damage to down. Machine guns and cannons cannot damage them, requiring 250lb+ bombs to one-shot the vehicle. These vehicles are found on higher tier maps where bombers (and some fighters) are able to carry the required heavy bomb loads to kill them. This class of vehicles is made up of heavy tanks.
Tactics and Tips
When attacking ground targets:
- Stick to the roads- using the roads as guides can help you tell where you target will be when the bomb or bullets get there.
- Keep your speed up- a slow target is an easy target! Keep your speed up to avoid enemy fighters getting on your tail.
- Remember travel time- bombs take time to fall, so aim where they will be when the bombs hit the floor.
- Don't forget your surroundings- diving on ground targets while there are enemies around will only get you killed, wait for an opening or back up.
- KAMIKAZE! - if you can't avoid crashing, for one reason or another, try to aim for a ground target, you will get XP and Lions if you kill the target in the explosion. Note: as of update 1.37 it is impossible to kill ground units and ships with kamikaze
- Pull up- don't get too close to the ground, as you risk killing yourself, whether it is by your own bombs or by hitting a tree.
- Leave the easy targets- if you are flying a bomber, go for targets that can only be killed by bombs and leave unarmored targets for friendlies. TEAMWORK PEOPLE!
- Use the turrets- in Realistic Battles, turrets have unlimited ammo, so use them to kill light targets instead of your limited nose guns.
- Use the small guns- using all your cannon ammo on ground targets will leave you in trouble in a firefight, use lower caliber rounds on light vehicles, saving the shells for later.
- Use cruise control- using cruise control allows you to sit back after you press a button, and watch your tank slowly drive on. Hands free way to relax and enjoy.