Lufthansa chief executive Carsten Spohr said Thursday he was "stunned" by suggestions the co-pilot of the jet operated by its Germanwings subsidiary had deliberately crashed the plane.
Spohr told a news conference there was "no indication what might have led" to the actions of Andreas Lubitz.
He said that 28-year-old Lubitz had passed all psychological tests required to begin training and underwent regular physical examinations.