However, the closest you'll get is "air," which is pronounced the same but refers to the mixture of gases surrounding the Earth.
It's worth noting that the word "heir" can also be used as a verb, meaning "to inherit" or "to succeed to a throne," and in this case, it might be confused with the verb "to air," meaning "to ventilate" or "to broadcast."
While not true homonyms, it's important to be aware of these similar-sounding words and the potential for confusion.