Airline breaches order by American president (5)
I believe the answer is:
obama
'american president' is the definition.
(I've seen this before)
'airline breaches order by' is the wordplay.
'airline' becomes 'ba' (British Airways).
'breaches' becomes 'ma' (I can't explain this - if you can you should believe this answer much more).
'order' becomes 'o' (abbreviation e.g. in British honours OM, OBE etc.).
'by' means one lot of letters go next to another.
'ba'+'ma'='bama'
'bama' put after 'o' is 'OBAMA'.
Can you help me to learn more?
(Other definitions for obama that I've seen before include "Important figure" , "44th US President" , "President awarded the 2009 Nobel Peace Prize" , "Trump's predecessor" , "in the White House" .)