HOLIDAYMAKERS face potential travel chaos next summer amid speculation flights could be grounded if the UK leaves the EU without a deal.
There are fears UK airlines and coach operators will be frozen out of Europe in the event of a 'no deal' Brexit.
It comes after the latest British government guidance reveals that if there is no agreement, airlines will have to obtain individual permissions to operate between the UK and the EU.
Major flight disruption could be created and some bus and coach service suspended with firms unable to access the continent.
The guidance also suggests that British road hauliers could be banned from the EU. But the government document states that the UK "would envisage" allowing EU airlines to continue flying and "we would expect EU countries to reciprocate in turn".
It added: "It would not be in the interest of any EU country or the UK to restrict the choice of destinations that could be served, though if such permissions are not granted, there could be disruption to some flights".
However, with the situation likely to affect holidaymakers in Northern Ireland and the Republic, Dublin Airport last night said it was observing the unfolding situation
"The European Union and the British government are working to ensure that in the event of a no-deal Brexit, flights between the UK and EU member States will not be affected," a spokesman said.
"We are continuing to monitor the situation closely, as are Dublin Airport's many airline customers."
Belfast International Airport declined to comment.
Ryanair boss Michael O'Leary has repeatedly warned that flights could be grounded if an aviation deal is not reached as part of the Brexit negotiations.
The government insists a no-deal Brexit "remains unlikely given the mutual interests of the UK and the EU".
Luton-based carrier easyJet created an Austrian division in July 2017 to allow it to fly between EU countries after Brexit.
Flights between the UK and 17 non-EU countries, such as the US, Canada, Switzerland and Iceland currently operate due to the UK being a member of the EU.
The guidance states that "replacement arrangements will be in place before exit day".
The UK has already reached agreements with a number of these countries and is "confident the remaining agreements will be agreed well in advance of the UK leaving the EU".