Dubai: Travelling in and out of the United Kingdom could get “very complicated” if the country votes to leave the European Union next month, Lufthansa Group board member Harry Hohmeister warned on Wednesday.

EU membership is not as important for the airline industry as it is for other companies but Hohmeister warned a leave vote “could bring some complications.”

Currently, the 28 EU member states grant visa free travel to each other’s citizens. There is a concern this could be removed for Brits travelling into the EU and for Europeans to the UK if the country does vote to leave.

“Everything is getting very complicated for the customer again,” Hohmeister, who as chief of hub management is an executive board member, told reporters at briefing in Dubai.

He cautioned that even if the UK left and got a similar deal to Switzerland, who as a non EU member enjoys some benefits including visa free travel, it could still “have an influence on the traffic rights on traffic rights negotiations.”

“I can just say I hope it will not take place,” he said.

Several European airlines have come out in support for the UK to stay in the EU, including the heads of British Airways parent company International Airlines Group (IAG), Britain’s easyJet and Ireland’s Ryanair. In February, Lufthansa Group chief executive Carsten Spohr said Britain should stay in as a political counterweight to the French.

Britain will head to the polls on June 23 to decide in a referendum whether the country should stay or exit the 28-member state European Union.