Likely large airline is taken aback by investigation (8)
I believe the answer is:
probable
'likely' is the definition.
(similar in meaning)
'large airline is taken aback by investigation' is the wordplay.
I cannot really see how this works, but
'large' could be 'l' (eg in clothes sizes) and 'l' is found within the answer.
'airline' could be 'ba' (British Airways) and 'ba' is located in the answer.
'is' could be 'be' and 'be' is found within the leftover letters.
The remaining letters 'pro' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for probable that I've seen before include "Likely to be the case" , "Seeming to have a good chance of happening" , "Like to happen" , "Person most likely" , "on the cards" .)