John Donne's poem "Aire and Angels" points out the separation between physical love of this world and that which is heavenly. This is, in fact, one of the many themes in Donne's poem:
...love and the world of the flesh versus spirit worlds...
The speaker is aware of physical nature of the woman he is writing about. However, he notes that some women seem to be not of body, but of air.
"Then as an Angell, face, and wings..."—Angels who appeared to men did so by 'assuming' a body of thickened air, like mist...
In Nicole Smith's article, "Poem Analysis of 'Air and Angels' by John Donne : Summary of Themes and Meaning," the author notes the similarity of Donne's poetry to that of William Shakespeare. For example, love is seen as something that reaches beyond what can be understood by "human thought and comprehension," as it comes from heavenly realms.
For Donne, however, while the body may house the soul, it simply provides a resting place for love. The speaker's observations are not based simply on the transient nature of the flesh which ages over time, but looks to the purer form of spiritual love that transcends the weak and changeable form of the flesh. So the struggle in the poem is between physical love and spiritual love.
In Shakespeare's Sonnet 18, the speaker speaks of his love's beauty, more lovely than "a summer's day." However, he is mindful, too, that time will take its toll on this physical beauty:
Rough winds do shake the darling buds of May.
He is aware that as time passes, her beauty will fade, for it is temporary. The first two quatrains (four-line stanzas) make it clear that the speaker can spend his time praising her beauty, but that in time, it will pass. The shift of the tone of the sonnet comes at the beginning of the ninth line:
But thy eternal summer shall not fade...
The author does not worry about how time will dim her beauty and that Death will eventually take her life: he makes her immortal in the lines of his poem. He writes:
So long as men can breathe or eyes can see,
So long lives this and this gives life to thee.
Whereas Donne's poem concentrates on the lack of importance of physical beauty, looking more toward the spiritual while in the earthly realm, Shakespeare seems to look to the physical, but with a a realistic sense of the passing time: that the physical (as with Donne's poem) is not the most important thing, but that the essence of the person existed within—beneath the flesh. And more so, Shakespeare is more concerned, above all, in making this woman immortal through his words.
Donne's topics were different than Shakespeare's:
Donne is best known for his metaphysical poetry on topics as diverse as the joys of lovemaking and humanity's subservience to God.
...is the supreme interpreter of human relationships, the supreme percipient of human frailties and potentialities.
And while he was influenced by the "Christian neo-Platonism of his day," he did not concentrate on the spiritual as did Donne, but more on the here-and-now, while hoping by his writing to capture the essence of those he wrote about on paper, even after time had taken its toll.