In "The Jilting of Granny Weatherall," passages such as these serve as figurative language to describe the foggy mind of the dying protagonist. The doctor, for example, is in no way literally floating, but it most likely seems that way to Granny, whose perception becomes more and more vague and dreamlike the closer she gets to death. This is contrasted with Granny's assertive and powerful manner of narration, given that she seems very willful, even in the face of death. However, there are many passages that show that she is simply unaware that she is dying.
Strange figurative language becomes more and more frequent as the story reaches its climax. For example, she compares her daughter Cornelia's voice to a cart that she then claims to physically climb inside. Poetic language such as this beautifully illustrates the ethereal state of Granny's perception of death.