This paper offers an overview of the state of research on airline partnerships and related issues: antitrust immunity, and joint ventures. While at a high level the potential pro- and anti-competitive effects of various forms of airline partnerships are well understood; a number of important gaps in our knowledge remain. For instance, academic research has yet to develop a clear way to differentiate between codesharing with and without immunity, and joint ventures with the use of the conventional IO modelling apparatus. Developing such theoretical models can be useful for policy makers. Future empirical research should focus on understanding the effects of joint ventures—as well as evaluating efficiency benefits of airline partnerships—and determining whether multimarket contact and repeated interaction could have led to the competitive environment that is conducive to tacit collusion.