Dubai: The United Kingdom’s aviation industry risks “chaos” if the government fails to reach a deal with the European Union on Brexit in the next five months.

The International Air Transport Association (IATA) warned on Wednesday that the increasing risk of a no-deal Brexit will hurt passengers and cargo, creating disruption if no transition plan is put in place.

With the UK set to leave the EU at the end of March 2019, IATA said the two sides urgently need to ensure connectivity remains post that date so that aircraft will still be permitted to take-off and land between the UK and European countries.

“With the possibility of a no-deal Brexit still on the table this late in the game, it is now essential that the EU and UK civil aviation authorities plan for contingency arrangements to maintain a minimum level of connectivity, which is vital for people and for business,” said Alexandre De Juniac, director general and chief executive officer of IATA.

The airline industry body added in a report on Brexit that even in the best-case scenario, where a Brexit transition period is agreed upon, “a high degree of uncertainty and risk” remains for the aviation industry. A no-deal or even a so-called ‘hard Brexit’ is likely to lead to “significant disruption to air services.” IATA said.

De Juniac pointed that the lack of transparency concerning the UK’s plans is leaving airlines in the dark, and said the industry “urgently requires transparency” so it can make plans for after March 2019.

As for the cargo segment specifically, IATA said the situation is even more complex.

“The most likely scenario, even under a transition period, is for shipments to be delayed or disrupted as new customs procedures become established,” IATA said in a statement.

The UK voted to leave the EU in June 2016, and with just five months to go till that exit, Prime Minister Theresa May is yet to reach a deal with the EU, with many British politicians and citizens backing a second referendum to vote on Brexit.