High scoring aptitude testing etc proves only one thing : you are good at aptitude testing. They hope that a strong correlation exists, and translates into actual ability. Answer, not always.
The old RAF / BAe flying college 14 hour grading course was a far more certain way of spotting talent. Far more expensive than computerised testing, but if you intend to invest well over £100,000 then I think it is money well spent.
You do of course need instructors fully trained in this specialised process.
It worked well for 90/07 courses onwards, as proved convincingly with CATHAY students.