sentences:  The airline previously conducted FAR Part 121 passenger operations in Alaska and Texas as well as providing charter service for gambling junkets.As of 1999 the company has ceased passenger operations to focus on the main aspect of its business, which is providing freight services to FedEx and UPS.Its headquarters is Billings, Montana, with hubs at Miami International Airport and at Luis Muñoz Marín International Airport, San Juan, Puerto Rico.