Southwest is known for short turnarounds to optimize airplane in-air time, which decreases costs. However, it seems like short turnarounds could be at odds with "optimal" refueling. Being able to add just enough fuel during a stop so that the plane can reach the next destination (plus safety margin) optimizes for weight, which also decreases cost.

Does anyone know more about Southwest refueling policy? In particular:

1) How much does WN's short turnarounds affect refueling? For example, if ~25 minutes is always enough to top off a 737, then I guess there's no issue!

2) I guess there's two extremes, given that WN has no redeyes: (1) only refueling overnight and never refueling at stops or (2) refuel at every stop. Anyone know if WN follows (1), (2), or something in between?