The nature of the North American airline loyalty landscape can be categorized by a few major players that maintain immense control over the market, with programs like United Airlines’ MileagePlus and Delta Air Lines’ SkyMiles having millions of members each. As a result, these programs can negotiate lucrative credit card partnerships that allow them to continue driving passenger loyalty while also opening up a new stream of revenue, as credit card companies will buy miles in bulk to use them to reward their customers.