The Thomas Cook logo is seen in this illustration photo January 22, 2018. REUTERS/Thomas White/Illustration

BERLIN (Reuters) - Thomas Cook Airlines TCG.L believes a transition period following Britain's exit from the European Union is important to allow time to clarify new rules regarding flying rights, ownership and safety regulations, an executive said.

“The clock is ticking,” Christoph Debus, head of the travel group’s airline business, told Reuters in an interview at the ITB travel trade fair. “Brexit is coming in March 2019 and we are already selling tickets for summer 2019.”

British airlines currently have unlimited flying rights to, from and within the European Union as part of an EU’s single aviation market. Carriers must be majority EU-owned to exercise those rights.

After Brexit, it is not clear what agreements will govern flying rights between Britain and the remaining EU countries or what Britain’s status within the bloc’s aviation safety regulator, EASA, will be.

“I believe that there will be a solution, but the question is how quickly,” Debus said, saying a two-year transition period in which everything remains according to current rules while details are cleared up would be desirable.

Earlier this week, the boss of British Airways parent IAG ICAG.L , Willie Walsh said he was convinced a solution would be found, although Ryanair's RYA.I CEO predicted disruption in April 2019.