Minecraft wiki entry for Levitation, associated text: The Levitation status effect normally raises the entity into the air, unless the entity is in water.
The player can walk/run while having the Levitation effect, especially on level 254.
Using /effect <player> minecraft:levitation <time in seconds> 255 makes the player fly in Survival and not jump, when the effect is over in Survival when in midair, hitting the ground causes the player to shoot into the air, resulting in a likely death.
If a player uses /effect command to self-grant levitation 256, the player moves at 230.4 blocks per second.