To shrink to a profitable size will require layoffs. Attrition won't cut it, especially in this economy where attrition is way down.Not all reductions result in layoffs. Theres always going to be a certain amount of attrition. If you shrink slowly you can shrink without anyone losing their jobs.
And by "shrink" I don't necessarily mean individual airlines getting smaller. I am talking more on an industry-wide level. That can happen with a major player simply shutting down (which, of course, would certainly mean layoffs).