Why Do Competing Airlines Allow Reciprocity for their Frequent Flyer Miles?

United and US Air offer routes that Continental doesn’t. By working together, they can drive business to each other against other airline alliances. For instance, United does the West Coast pretty well, and so does Alaska. Continental helps United get passengers to the southeast, which is Delta country, while Alaska routes Delta customers along the west coast. Airline alliances and code-sharing provide a lot of savings on routes that individual airlines may not be able to fly.

Why does Pizza Hut accept competitor’s coupons? It’s good for business.

Frequent Flyer Miles are a sham

Of note is that it may not be a 1 to 1 trade. For example, I flew an AA codeshare with British Air, and while they gave me some miles for the BA segment, it was no where near what it should have been had it been AA all the way.