An unidentified person on Monday left a message across the skies of Australia's Brisbane city saying, 'I'm Sorry'.
Pictures of the airborne apology splashed across social media within minutes, the Brisbane Times reported.
The fee for the message was A$4,000 ($3,000) but the operator of the service, Skywriting Services Australia, said they had no idea who the message was meant for.
The operator said that for now he could only confirm the person behind the apology was a man and an "interesting guy".
But the man who requested for it did not appear to be frantically lovelorn, he said.
The author and recipient of Monday's message remains a mystery.