(July 24, 2019, 7:49 AM EDT) -- ST. LOUIS — An air ambulance company on May 9 filed a brief in the Eighth Circuit U.S. Court of Appeals contending that a district court wrongly determined that its membership plan constitutes an insurance business that is governed by North Dakota law. The company maintains that it is entitled to federal preemption of state law (Guardian Flight LLC v. Jon Godfread, et al., No. 19-1343, 8th Cir.)....