The disposition of the 717 is definitely the biggest question mark on the NB side of things right now. Up until early this year everything was pointing to a ~2030 start to the draw down of the fleet. The wing spar issue is an unexpected and ongoing concern that very well could spell an early demise for the fleet. Replacing 80 planes over a 2 year period is a tall order right now with deliveries from Boeing and Airbus continually slipping to the right. It seems all but certain that an early retirement of the 717 fleet will cause other fleets to have to delay retirements.