Airlines maintain complex networks that are to large extents complementary. Therefore, some passengers need to change aircraft and airlines to fly from their origin to their final destination. The present study captures pricing problems in terms of double marginalization but goes one step further by incorporating network choices. The model involves a two-stage game with two carriers who choose their complementary networks in the first stage and fares in the second stage. Each carrier's network involves one or two links that are distributed geographically or distributed in time. If both carriers maintain two links, then transfer passengers can choose between two alternative connections which they consider as imperfect substitutes. There are only transfer passengers, and maintaining a link is costly. The analysis reveals that carrier collaboration and antitrust immunity can eliminate double marginalization and create incentives to extend networks. Our results indicate that the scope for the improvement of carrier networks via antritrust immunity can be rather limited relative to the social desirability of more extensive carrier networks. A possible policy lesson is that airlines should be granted antitrust immunity conditional on network expansion and/or frequency obligations.

航空公司维护着复杂的网络，这些网络在很大程度上是互补的。因此，一些乘客需要将飞机和航空公司从原点飞往最终目的地。本研究从双重边缘化的角度捕获了定价问题，但通过合并网络选择，又向前迈进了一步。该模型涉及一个分为两个阶段的博弈，其中两个运营商在第一阶段选择他们的互补网络，在第二阶段选择票价。每个运营商的网络都涉及一个或两个链路，这些链路在地理上或时间上是分布的。如果两个承运商都保持两个链接，则转机乘客可以在他们认为不完善的替代品的两个替代性联系之间进行选择。只有中转乘客，并且维持联系是昂贵的。该分析表明，运营商的协作和反托拉斯豁免权可以消除双重边缘化现象，并可以激励人们扩展网络。我们的结果表明，相对于更广泛的运营商网络的社会可取性，通过反托拉斯豁免权改善运营商网络的范围可能相当有限。一个可能的政策教训是，应根据网络扩展和/或频率义务为航空公司授予反托拉斯豁免权。