As for the comments on old vs new planes, blve that it takes about 12-18 months to de-bug a new plane and make it really reliable (sort out the wiring looms etc), so don't knock your used planes, someone has sweated hard to make them right...
- I also recall
PR's issues with some 747's it acquired off an airline in the same region that only use new planes, turned out that airline hadn't bothered to upkeep the anti-corrosion regime recommended because it was cheaper, cost poor old
PR a fortune to rectify.......