To find the best education, you first have to define what "best" actually means. I would hazard a guess that the best education for a specific airline is their own programme as you are taught what that particular airline wants you to know. There are a few schemes around still. Learn German and you can have a go at Lufthansa's scheme if you pass their rigorous selection process
As for the most expensive education, well, if you have the mullah, I can set you up with a pretty expensive education that will let me retire in a year