Chapter 11

I know Chapter 11 bankruptcy means that an airline can file for bankruptcy, but has time to reorganise it’s finances. But how long are they given? Who runs the company in the meantime? What if the stratagy doesn’t work? So many american airlines have gone into Chapter 11, then come out again, then gone back in, and some have never come out, but none of them have ever gone completly under. Why is this? I just don’t get it, it’s like Chapter 11 prevents an airline ever collapsing completely, no matter how bad their finances are, they just seem to keep going forever. Help!