Capt. Robert Miller sends his creditors a minicommercial for Republic Airlines with every bill he pays. Recently a creditor sent one back. Captain Miller, of Casselton, N.D., flies for Republic Airlines. For the past four months, he has included company-supplied promotion material with every bill he's paid. His water bill included this message: ''Here is my check. I enjoy doing business with you. My company is Republic Airlines, and I am asking you to enjoy doing business with me. Republic is a great airline, offering good service , competitive fares, and we can take you throughout the United States, to Canada , Mexico, and the Cayman Islands. When you fly, try us.''
Casselton City Auditor Reuben Braaten replied: ''Here is my receipt. I enjoy doing business with you. My company is the City of Casselton and I am asking you to enjoy doing business with me. Casselton is a great city, offering good services, competitive taxes, and we can take you throughout the city in no time at all.''
Republic began the bill-stuffer program in October. Each of Republic's 14,000 employees received a supply of promotional messages and ''Fly Republic'' stickers to include when paying their bills in a companywide effort to call attention to the airline and its route structure.