The term "Focus Cities" refers to a group or cluster of airports that an airline chooses to focus on for expansion and growth. These are typically smaller, secondary airports in major metropolitan areas where demand is high but there may be less competition from other carriers. By focusing on these cities, the airline can increase its presence and market share without having to compete directly with larger hubs or competitors at primary airports. This strategy allows the airline to target specific markets and demographics while potentially reducing costs by operating out of smaller facilities.