1 From Louisville to Green Bay, the most frequently used aircraft is an Embraer ERJ 135/ERJ 140/ERJ 145. 2  On average, flights from Louisville to Green Bay are cancelled 0.6% of the time. 3  4.8 percent of flights from Louisville to Green Bay are delayed.
I agree that big cities are pegged at around the 2 million mark. I think of medium cities as being between 500,000 and 1.5 million. Small cities are less than 500,000 but more than 100,000. Anything under 100,000 is a town to me, not a city.
A large city would be considered a population as long as only one species is being discussed/studied e.g humans in London, ravens in Mirpur, goats in Lahore etc. The same city would be considered a community if more than one species are being discussed at a time e.g humans,plants bacteria,ants etc. in London.