When you have elytra equipped, you can jump over 2 blocks by tapping space rapidly while holding W. It takes a while, but it will eventually work if you keep trying.
Related issues
duplicates
Comments
migrated
MC-99881
You can jump over walls with Elytra
Resolved
Duplicate
0
migrated
migrated
(Unassigned)
Unconfirmed
Minecraft 1.9, Minecraft 1.9.1 Pre-Release 1, Minecraft 1.9.1 Pre-Release 2, Minecraft 1.9.1 Pre-Release 3
Retrieved
Works As Intended due to future fix of MC-90591.
If not, then likely a duplicate of MC-90591.