Ryanair has been forced to cancel nearly 170 flights today as a strike by French air traffic controllers causes travel chaos for air passengers.

The strike which got underway today is expected to last for six days.

Aer Lingus meanwhile says its services to France, Spain, Portugal and the Canary Islands have seen significant delays of up to three hours today.

They are warning it will have a knock-on affect on other services throughout the day.

Passengers are still advised to turn up at the airport on time and to check-in for their flights.

Airports in the UK have also been hit, with EasyJet having to to cancel about 25% of flights.

The company has advised people against re-booking journeys between today and June 30th because of the likelihood of further disruption.

Cancellations and delays may be significant but are not expected to be as bad as first feared. One of the two French unions involved called off its action after talks.

The unions are opposed to plans for a re-organisation of air navigation in France. Airports and airlines have been planning in an effort to avoid as much of the disruption as possible.

Grace Duffy of the European Consumer Centre has this advice for anyone affected.

Lisa Cleary is stranded in Reus Airport in Spain, after her Ryanair flight to Dublin was cancelled this morning.

She is waiting in a long queue with what she says is 200 other stranded holidaymakers.

The strike is in opposition to the "Single Sky" initiative of the European Commission. It is is aimed at lessening congestion in European airspace and accommodating expected increases in traffic, by allowing planes to fly more direct routes across the continent.

France is set to join Germany, Switzerland, Belgium, the Netherlands and Luxembourg to create a regional authority.

But this proposal has come under fire from unions that are worried about the consequences of the plan, including its effect on jobs.

The networks handle some 9 million flights each year in a region with about 440 airports.