Month of May
In this simile, the narrator describes how far the Kwuggerbug was blown after Horton sneezed: "And they blasted that Kwuggerbug so far away, that he sailed thru the air for the whole month of May."
Walking on air
Horton uses a metaphor to describe how he can't fly when the Kwuggerbug asks him to retrieve the beezlenuts:
"I can't walk on air, if you see what I mean." metaphor for flying
The Lake
The lake represents the fact that Horton's part of the deal is harder than expected. This is also a metaphor for the fact that the Kwuggerbug is not putting in the same amount of effort.
The legs and the brains
The Kwuggerbug uses a metaphor to describe the role of himself and Horton in the deal: "You furnish the legs and you carry me there... I'll furnish the brain."
The Mountain
Again, the mountain is a metaphor for the difficulty of this journey for Horton. On the way up, Horton is hurt and bruised by the rocks on the mountain, while the Kwuggerbug is safe and free from harm. This is an indication that the deal between the two is unfair.