187.55 Overflight fees billing and payment procedures.
(a) The FAA will send an invoice to each user when fees are owed to the FAA. If the FAA cannot identify the user, then an invoice will be sent to the registered owner. Users will be billed at the address of record in the country where the aircraft is registered, unless a billing address is otherwise provided.
(b) The FAA will send an invoice if the monthly (based on Universal Coordinated Time) fees equal or exceed $400.
(c) Payment must be made by one of the methods described in 187.15(d).