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- Ryanair's CEO criticized Wizz Air's unlimited flights pass as a "marketing scam."
- He said the flights could sell out before pass holders had a chance to book them.
- A Wizz executive described his comments as "provocative" and "inaccurate."
Tensions are growing between two of Europe's top budget airlines after the Ryanair CEO called Wizz Air's unlimited flights pass a "marketing scam."