Currently Wizz Air Hungary operates as W6, and most (if not all) Wizz Air UK flights operate as W9. Wizz Air Malta has a W4 IATA code,
AFAIK, use a W6 code, except for the occasional special charter or positioning flight. Yes, I know Wizz Abu Dhabi has 5W, but they are somewhat separate to the rest of the company.
I recall reading somewhere that Wizz Air Malta might start using W4 for normal scheduled flights in its own right, but can't remember where I read this... but I do remember wondering if this was really true or just a bit of unreliable gossip.
Would anyone in the know care to comment on this ?