Burlington VT - ARFF at airport is done by natl guard

iirc there are 35 civilian airports in usa protected by the military -
maybe for free

https://dwuconsulting.com/images/OS/BTV%202021A%20OS.pdf

The Airport is certificated by the FAA in accordance with 14 Code of
Federal Regulations (CFR) Part 139, Airport Certification. The City is
required under 14 CFR Part 139 to comply with FAA operating and safety
standards, including the provision of aircraft rescue and firefighting
(ARFF) services at the Airport during the hours of airline activity.
Annual ARFF O&M Expenses, along with equipment and capital expense,
are provided by the Vermont Air National Guard (VTANG). The City
estimates annual savings of approximately $2.5 million in O&M Expenses
because VTANG provides ARFF services at the Airport. It is assumed
that VTANG will continue to provide ARFF services at the Airport to
meet the requirements of 14 CFR Part 139 during the Projection Period
at no cost to the City.