Nashville international airport(BNA) is a Large Airport Hub which account for more that 1% of total US passenger emplacements, with annual passenger emplacements over 12millions. 2 million more than Honolulu (HNL) and Chicago midway (MDW), of which both airports are scale 7.
I think Nashville deserves a Scale of 7
Wiki data:
Also Nashville is a major Tourist destination in US, the country music capital of US, also the health care capital. One of the best Metro Area for professional and business service Jobs.
Under economy section(wiki):
Nashville has close to 17 millions visitors per year. More than $11.22 billions spending by the visitor annually.
See link:
In 2023, Nashville welcomed 16.83 million international and domestic visitors indicating a 4% increase from the previous year.
Based on Nashville GDP in 2024(provided in Nashville wiki link) tourism provide more that 5% of the city's annual GDP directly.
Nashville definitely deserves a vacation hub charm, possibly a financial hub charm as well.