What is Air-Way?

Legal Definition
In English law. A passage for the admission of air into a mine. To maliciously fill up, obstruct or damage, with intent to destroy, obstruct or render useless the air-way to any mine, is a felony punishable by penal servitude or imprisonment at the discretion of the court. 24 & 25 Viet. c. 97, § 28.
-- Black's Law Dictionary