If you have a booking with WOW Air, you need to keep a very close eye on it.
The airline appears to be on the cusp of going bankrupt. Icelandair has walked away from its agreed deal to buy the airline (we wrote about that here) and on Wednesday the airline handed back two A330 and two A320 aircraft to their lessors.
Whilst the airline is still flying as of today, you should start to research a back-up plan if you have tickets. This may include, for example, booking Avios redemptions on the same routes which can be cancelled for £35 if WOW does survive.
(EDIT: overnight on Thursday, a US venture capital group announced – subject to due diligence – that it would invest in WOW. Whilst not guaranteed, if this goes through it should take the pressure off for a few months.)