NationAir is one of the largest and oldest aviation insurance brokerages in the United States. NationAir clients span the entire spectrum of general aviation and are located all across the United States. We serve our clients through our home office at the Spirit of St. Louis Airport located in suburban St. Louis, MO , and through our branch offices located throughout the country. Our company structure allows us to offer our clients the influence of a large, national brokerage and the ability to create a personal relationship with their broker.