I think many people don't appreciate just how much of the US population is packed into the largest metro areas. If you re-drew the map of the country weighted by population, it would look like this:



And if you re-weighted based on GDP (a good proxy for business travel demand), it would look like this:


Basically those passengers going from LaCrosse to Jacksonville are rounding errors. What you really want, as an airline, is big chunks of those big-city bubbles. Unless you're Allegiant of course.