US, April 27 -- When Scott Kirby publicly described his vision for a merger between United Airlines and American Airlines, he framed it not as consolidation, but as transformation - a rare attempt, he suggested, to grow rather than shrink an industry long defined by retrenchment.

But beneath the aspirational language - "growth," "customer value," "global leadership" - lies a more complicated question: Is such a merger realistic in today's regulatory and economic climate? And what, if anything, went unsaid?

The Promise: Growth Without Pain Kirby's argument rests on a deliberate break from history. Airline mergers - from Delta-Northwest to United-Continental - have typically been justified as survival strategies. Costs are cut, overlappin...