I analyze the spatial relationship between entry and airfares in the U.S. airline industry. I define the spatial relationship between adjacent airports based on catchment overlap, and evaluate the spatial impact of entry on fares. Using a fixed-effects estimator, I find that the impact of LCC entry on prices is not only larger than that of Legacy entry, but also influences prices at more distant airports. Owing to endogeneity concerns in the estimates, I also consider quasi-experimental evidence from the expiry of the Wright Amendment, which resulted in rapid and dramatic entry by Southwest Airlines from Dallas. Echoing the descriptive results, I find a broad spatial impact of entry by Southwest on rivals’ airfares. Overall, evidence suggests that current approaches to market definition in the airline industry may be overly restrictive, and I recommend researchers consider grouping a broader set of airports when defining markets.

我分析了美国航空业的入境和机票之间的空间关系。我根据集水区重叠定义了相邻机场之间的空间关系，并评估了进入对票价的空间影响。使用固定效应估计器，我发现 LCC 进入对价格的影响不仅大于 Legacy 进入，而且还影响更远机场的价格。由于估计中的内生性问题，我还考虑了赖特修正案到期的准实验证据，这导致西南航空公司从达拉斯迅速而戏剧性地进入。与描述性结果相呼应的是，我发现西南航空的进入对竞争对手的机票产生了广泛的空间影响。总体而言，有证据表明，目前航空业市场定义的方法可能过于严格，