Though fatigue is certainly a part of the Airline Safety and Pilot Training Improvement section of this bill, its not really what the airlines are opposing. They're opposing the fact that if, given a 1500 hour rule, they would be forced into increasing compensation. Why? Because generally speaking, newer pilots are willing to work for less - which is absolutely not to say that there's anything wrong with that. But the fact is that given industry predictions of a pilot shortage rivaling the 2007 levels and this legislation combining to create a "perfect storm," airlines may be forced into parking planes.
Look I hate to be cynical, and I know there's an enourmous faction of this website that totally disagrees with my position on the legislation...we'll see in 3-5 years time. It's sure going to be tough (when our Congress is holding hearings on the possible catastrophe that our nation's air transportation system may be in due to a pilot shortage) to NOT point fingers and say "we told you so."