Welcome to the amazing world of the AirDyne. Generally speaking the AirDyne is "easy" conditioning, even when pushed hard. Yes, there is a limit but few actually reach it. Anyway, use the AirDyne as a substitute for the walk, as a warm-up prior to lifting (10-15 minutes) or on your days off. You can also use it prior to the Prowler (again, warm-up). ALWAYS do the Airdyne PRIOR to mobility work.
Despite it being a great tool, any kind of "rote conditioning" can still make you stiff so either do it BEFORE mobility work or as PART of a mobility circuit (recommended).