In December 1994 the Department of Transportation sent a letter to US airlines (.pdf). It said that failure to make award seats available to customers could be a prohibited deceptive practice.
The Department’s deceptive practices prohibitions preclude airlines from imposing unreasonable capacity restrictions and/or unannounced blackout dates for the use of frequent flyer awards.To the extent airlines offer their frequent flyers awards for service to destinations, that traditionally are subject to high consumer demand, they must include in their promotional materials adequate disclosure that seats are limited—at times severely—and may not be available on every flight, if in fact that is the case.
The Department understood that frequent flyer awards might not be available on high demand routes at peak demand times, and if that’s the case programs needed to provide adequate disclosure of that fact.
They never even thought to address airlines which failed to make award seats available on a route ever.
Of course the DOT’s Inspector General found that the department improperly ignores consumer complaints regarding frequent flyer programs.
So while the Supreme Court said that consumers can’t raise state court claims against frequent flyer programs that’s ok because consumers have the DOT, the DOT says consumers don’t actually have the DOT.