Try the Commands Troubleshooting and Help page if you get stuff with server errors.
Summon falling blocks and ghost blocks
Make a command for summoning a falling block entity. Make it hover as a ghost block, or give the falling block motion to launch it across the map. Falling blocks have similar properties as setblock, but are entities that can have motion, but also they have a life time limit.
Time
Measured in ticks this is how long the falling block will be in the world for. Time will increase at 20 ticks per second. If Time is set to 1, it will increase until it reaches 600 (30 seconds) or until it lands. If still falling it will drop as an item (if possible). Time can be set to negative, and will continue to tick up until reaching 0 at which point it will despawn. It is recommended to always set Time, as the default value of 0 will cause the falling block despawn instantly.
This block will fall for 30 seconds or until it lands
/summon falling_block ~ ~ ~ {BlockState:{Name:cobblestone_stairs},Time:1}
Ghost blocks
Using the NoGravity tag allows the falling block to float in the air. Players can walk or fall though Ghost blocks, ideal for map makers planning traps or secret passage ways. Due to the Time limit (above), map makers will need to use a redstone timer clock to repeat the respawn command.
This block will hover, and then drop as an item after 30 seconds
/summon falling_block ~ ~ ~ {BlockState:{Name:cobblestone_stairs},Time:1,NoGravity:1b}
This block will hover, and then despawn after 30 seconds
/summon falling_block ~ ~ ~ {BlockState:{Name:cobblestone_stairs},Time:-600,NoGravity:1b}
New in Minecraft 1.19 is summon block_display. Summon block display is the newer recommended way to put ghost blocks into the world.
Flying Blocks
Falling blocks can be make to shoot in any direction by setting the initial motion. Maximum of 10, or -10 for reverse direction. On hitting a wall the falling block will convert into a block as usual. With upward vertical motion (z axis), the block will eventually slow and then begin to fall.
Minecraft Versions Permalinks
If you find yourself using a particular version all the time, you can link directly. There is some crossover between versions, so there will be quirks.
Version History
added1.20.5+ Food, tools and new tags for give generator
patchMinor fixes for chest container items
patchBanner set block command
patchsetblock falling blocks missing tags for signs, banners and such
patchbanner base banner undefined
patchre-added generator link text for items that have their own generator
added1.21 potion effects
added1.21 banners patterns
patchseveral banner bugs
patcharmor trim colors
patchchanging item name deletes imported data
patchgive enchantment_glint_override
patchPotion better give with options
patchBetter grass
patchBetter utf8 character support.
addedUpdated page content command with version toggle
added1.21 particles
patch1.21 particles syntax issues on particles with extra options
patchCommand save to storage issues
addedAllow attributes ids to be set for 1.21, name for before 1.21
addedNew attributes and removed uuid for 1.21
patch1.20.5+ give summon item name and lore
patch1.20.5+ tag to custom_data
patchCaching changes for icons
addedCache busting for updates
addedGive fake enchantment, potential fix
patchAttributes not importing correctly
patchIn some cases the enchantment tab disappears
added1.21 is now default
patch1.21 attributes name changed to id.
patchText editor single quote and escape character handling
added1.21 items
addedSome 1.20.5 particle support
patch1.20.5 Container item component nbt
patchText/Lore importing
added1.20.5 finished adding summon potion, firework, item, falling block, and block display support
patch1.20.5 fixed sweeping which had been renamed to sweeping_edge
added1.20.5 import for banners, enchanted books, fireworks, goat horns, knowledge books, player heads, potions, signs, and written books
added1.20.5 import for base command, and armor
added1.20.5 support for banners and premade banners
patch1.20.5 potion Ambient, Particles, Icon
added1.20.5 support for summon item
added1.20.5 support for signs
patchplayer head texture urls not working
added1.20.5 support for Enchanted Books, Fireworks, Player Heads
added1.20.5 support for Potions, Written Books
patchTargets not updating when updated
added1.20.5 support for Armor, Knowledge Books
patchItem search
addedGive generator migrated to version 2
addedBanner generator migrated to version 2
added1.20.5 predicates, sbt
Read version history »
(44 More Updates)