Legal Question in Employment Law in Missouri

Missouri employers can terminate employees for almost any reason (not discrimination for race, color, religion, sex, national origin). If I understand the question correctly, you are a replacement worker.

Because of the scope of your employment, you are in a middle-ground not covered by the collective bargaining agreement (CBA) and are not a contract worker. Therefore you could legally be fired for not traveling (or any "arbitrary or capricious reason).