The stinging attack follows the “unreserved” apology O’Leary was forced to make last week after Ryanair ran ads depicting Sir Stelios as Pinocchio and suggesting he was lying about easyJet’s punctuality.
The libel suit was settled out of court, with Sir Stelios accepting £50,100 in damages.
The “Pinocchio” campaign referred to Sir Stelios as “Mr Late Again” and called on him to “stop hiding the truth” about easyJet’s on-time performance.
Sir Stelios’ latest rap came in an open letter addressed to Sir Stelios’ “friends” announcing he is to donate the damages to charity.
The two carriers are in a constant battle, often via the Advertising Standards Authority. EasyJet won the latest round, having a complaint regarding fare availability against its low cost rival upheld by the advertising watchdog.