Taxis in the Sky

From The Atlantic by James Fallows: Taxis in the Sky about the emerging market for air taxis connecting smaller cities not served by point-to-point service.
“Herriott and Sawhill have developed a model to simulate the individual decisions that go into every one of these business trips. The model starts with the likelihood that a person in any one city, let’s say Mobile, will want to go to another, say Savannah, on any given weekday (for now, DayJet is a weekday-only service). These predictions are based on average income in each city, business relations, and other factors, and are constantly tuned to reflect real data. “It’s like the pull between two planetary bodies,? Herriott said. “Almost a Newtonian law!? (He was joking.)”
Could they be using a version of The Gravity Model, which implements a version of Tobler’s First Law of Geography “Everything is related to everything else, but near things are more related than distant things.”