Airfares around the United States generally are falling compared with last year, but exceptions include some pretty big markets. Even where prices aren't rising, years of capacity reductions in some places mean much less choice, fewer nonstop destinations and lower overall value. This forces travel buyers to rethink their air contracting strategies. Where the loss of air service is extreme, there's also an impact on local economies. It figures in as businesses consider where to expand. Meeting planners prefer markets with better . . .