The paper investigates the construction of a low-cost airline network by analyzing JetBlue Airways' entry decisions into non-stop domestic US airport-pair markets. Adopting duration models, we find that JetBlue consistently avoided concentrated airports and targeted concentrated routes; network economies also affected entry positively. For non-stop entry into routes that have not been served directly before, our analysis reveals that the carrier focused on thicker routes and secondary airports. Non-stop entry into existing non-stop markets, however, shows that JetBlue concentrated on longer-haul markets and avoided routes already operated by either other low-cost carriers or network carriers under bankruptcy protection. Copyright © 2012 John Wiley & Sons, Ltd.