- This paper considers a transport network with two firms that operate a parallel service on a hub-to-hub connection and monopoly services on spoke-to-hub connections under increasing returns to scale. We find the following: A symmetric equilibrium cannot occur under independent (non-cooperative) pricing when the number of spoke-to-spoke passengers becomes positive. The effect of cooperative pricing on mark-ups in spoke-to-hub, hub-to-hub and spoke-to-spoke markets (where double marginalization can occur) can be positive or negative. Cooperation can reduce total welfare though hub-to-hub markets are small.
