Moody's has published a list of bottom rung corporations based on their rating system.

Take this with a grain of salt, Moody's (along with others) rating system rated all of those subprime mortgages and their derivatives AAA which is why the economy is in this mess in the first place.

Here's some Aviation related companies:

AirTran Holdings, Inc
AMR Corporation
Arinc Incorporated
DAE Aviation Holdings, Inc
Evergreen International Aviation, Inc.
Hawker Beechcraft Acquisition Company LLC
JetBlue Airways Corp.
Landmark FBO, LLC
Orbitz Worldwide, Inc.
Pegasus Solutions, Inc.
Synchronous Aerospace Group
UAL Corporation
US Airways Group, Inc.

Cheers
George