I have been reading about DAL's efforts in this for a couple of months. Very interesting. They are going back to MORE spare aircraft and commercialing their crews out to pick up an aircraft and passengers when they think the scheduled crew is going illegal. They have even launched trans atlantic and planned to stop short of destination as the crew could not make it with 117. Backup crew flew commercial in and picked the aircraft up and flew it out an hour later.

Really thinking outside the box, and their operational metrics are blowing everybody else out of the water by 10 points.