Air

Air is an invisible, non-solid Block which occupies any space not filled with another block.

Overview

Air cannot be created, destroyed, or obtained, even with an inventory editor. Although it is technically a block, it is usually not seen as such, as there is no way to interact with it. Air is unique in the way that it automatically replaces any block that is removed, even though it doesn't visually flow. Air is required in order to avoid drowning from Water, or suffocation from falling Sand/Gravel.

Background

In the Indev versions, air affected fluid blocks that were horizontally adjacent to it. If air was touching a fluid block, there was a 2 out of 3 chance the fluid block would disappear and make the pool recede and a 1 out of 3 chance the fluid block would fill the air, making the pool spread. 

Trivia

• Air is programmed to fill any adjacent blocks that are not already full. Sometimes, there is a glitch where a Player takes suffocation damage when blocking water, or emptying the block of anything other than air that the player is standing in.
• Even though air is nonexistent in The Void, a player does not suffocate. They are just unable to place blocks beneath the Bedrock level.
• In Alpha/Beta/release 1.3, players could have the air block in their inventory.
• Air is one of the two types of blocks generated in all three Minecraft dimensions, the other being bedrock.
• Air is the most common block in Minecraft.

Blocks
Natural	Air • Stone • Granite • Andesite • Diorite • Bedrock • Clay( Terracotta) • Cobblestone ( Moss) • Cobweb • Dirt • Gravel • Coarse Dirt • Bone • Ice • Monster Spawner • Sand ( Red) • Sandstone ( Red) • Obsidian • Snow • Sponge • Wet Sponge • Stone Brick ( Cracked • Moss • Chiseled) • Prismarine ( Dark • Brick) • Sea Lantern
Manufactured	Bookshelf • Brick • Wool ( Carpet) • Concrete( Powder) • Conduit • Dried Kelp Block • Fence • Glass ( Pane) • Stained Glass ( Pane) • Glazed Terracotta • Hay Bale • Iron Bars • Jack-O-Lantern • Ladder • Painting • Scaffolding • Slabs • Slime • Snow • Stairs • Walls • Wooden Planks
Ore	Coal Ore • Diamond Ore • Emerald Ore • Gold Ore • Iron Ore • Lapis Lazuli Ore • Redstone Ore Nether Quartz Ore
Mineral Blocks	Block of Diamond • Block of Emerald • Block of Gold • Block of Iron • Lapis Lazuli Block • Block of Quartz • Block of Redstone • Block of Coal
Utility	Bed • Brewing Stand • Cake • Cauldron • Chest • Shulker Box • Crafting Table • Enchantment Table • Furnace • Jukebox • TNT • Anvil
Mechanisms	Button • Dispenser • Redstone Lamp • Door • Fence Gate • Lever • Note • Piston ( Sticky) • Pressure Plate • Rail ( Powered • Detector • Activator) • Redstone ( Wire • Torch • Repeater • Comparator) • Trapdoor • Trapped Chest • Hopper • Daylight Detector • Tripwire Hook • Observer
Plants	Cactus • Dead Bush • Chorus Plant • Flowers • Grass ( Grass • Fern) • Leaves • Lily Pad • Melon • Mushrooms ( Huge)  • Mycelium • Podzol • Pumpkin • Saplings • Sugar Cane • Vines • Wheat • Wood • Corals • Kelp
Liquids	Lava • Water
Non-Solid	Fire • Sign • Torch • Banner
The Nether	Glowstone • Netherrack • Nether Brick ( Fence)  • Nether Quartz • Nether Wart • Soul Sand • Magma Block
The End	Dragon Egg • End Stone • Purpur • Endstone Brick • End Rod • Dragon Head • Ender Crystal
Creative only	Barrier • Structure Block
Pocket Edition only	Stonecutter (old) • Nether Reactor
Technical	Piston Arm • Block 36 • Burning Furnace • Glowing Redstone Ore • Off-state Redstone Torch • Active Redstone Repeater • Flowing Water • Flowing Lava • Farmland • Pumpkin Stem • Melon Stem • Block 97 • Portal • End Portal Frame • End Portal
Unused	Locked Chest
Removed	Gear • Dirt Slab • Cyan Flower • Camera(PE)
Unimplemented	Barrel(1.14) • Bell(1.14) • Blast Furnace(1.14) • Campfire(1.14) • Cartography Table(1.14) • Compost(1.14) • Crying Obsidian • Fletching Table(1.14) • Grindstone(1.14) • Lantern(1.14) • Lectern(1.14) • Loom(1.14) • Smithing Table(1.14) • Smoker(1.14) • Stonecutter(1.14) • Sweet Berry Bush(1.14) • Jigsaw(1.14)