Flying KLM’s safer tho’ it maintains a constant temperature (7,5)

I believe the answer is:

thermos flask

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'it maintains a constant temperature' is the definition.
I know nothing about this answer so I cannot tell whether this works.

'flying klm's safer tho'' is the wordplay.
'flying' is an anagram indicator (letters fly around into new positions).
'klms'+'safer'+'tho'='klmssafertho'
'klmssafertho' with letters rearranged gives 'THERMOS FLASK'.

Can you help me to learn more?

(Another definition for thermos flask that I've seen is " Container for keeping drinks hot".)

I've seen this clue in The Times.

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