Flight chaos over Europe on Tues and Wed, what it meant for consumers.

From an interview on RTE's Morning Edition Thursday June 26, look back on rte.ie/player Morning Edition from minute 29 or so. 
Air Traffic Disruption over Europe – June 24-25
What
French Air Traffic Controllers called off strike following talks all day in France. Belgian air traffic went on strike for two hours in the evening from 6-8pm. The disruption from French ATC and Belgian ATC meant delays and cancellations for more than 70 per cent of flights in Europe yesterday.  The disruptions will still continue today Thursday June 26 and some passengers will still be trying to get to their destinations. This is  a very busy time of the year with the holiday season and most flights will be more than 90 per cent full making re-routing difficult.

IATA director Tony Tyler went so far as to say that the “timing of the strike could even be regarded as malicious.” as It is high season on travel across Europe.
Why
The strikes are in protest at the planned reforms to bring the management of Europe’s airspace into the modern era which would be delivered by a Single European Sky.  There are more borders over the skies of Europe than on land.  With more than 26,000 flights a day over Europe, this is seen as the best way forward to manage air traffic safely and more efficiently. It will also allow room to grow as air travel is expanding.
Know
Passengers who were disrupted over the past days should know that

While passenger rights are covered under European Union legislation particularly Directive EU261 which rules that air carriers must
1 offer you the choice of re-routing as soon as possible,
2 re-routing at a later dates of your convenience
3  or a refund.

As well as care and assistance which means meals and refreshments , hotel accommodation if you have to stay overnight, transport to and from accommodation and two free phone calls  and access to email.
See flyrights.ie
Losses not necessarily covered by Insurance
However if you were booked to stay in a hotel, or booked a car or any other tours, meeting rooms,  or events, you will not be refunded for them, unless you have a super duper travel insurance policy. 
Here’s where reading the small print comes in handy.  Unless your policy specifies, it will not cover you for cancellation of your flight or other elements of your trip.
I checked my own multitrip insurance policy yesterday and while I had paid for the premium product with all eventualities covered, I thought, it turned out I would not have been covered for flight cancellation as I did not specify it as an extra.  It would be an additional 27 euros.