"Have we had glitches?" CEO Jeff Smisek asked during a J.P. Morgan conference on March 13. "Of course. In a project of that size you have to. But we're knocking those down one by one. We've had high call volumes, no question about that, but those are really driven by some of the underlying issues we've had," such as difficulty with "the conversion of MileagePlus balances" and a glitch that landed some passengers in the incorrect boarding zone.