As it turns out it doesn’t actually cost that much on regular transit, there’s an AIRPORT SURCHARGE because it’s an “airport train”.
No wonder Americans don’t use public transit, even when the system exists it’s ridiculously difficult and expensive to use.
Pretty rarely, far as I know. I’ve seen some that cover public transit costs at least. It’s more common for them to only reimburse costs for travel during work hours or for business related trips.