BERLIN — Abu Dhabi-based Etihad and tour operator TUI Group have terminated negotiations on setting up a vacation airline joint venture that would have combined the latter’s TUIfly with a subsidiary of Germany’s struggling Air Berlin.

TUI board member Sebastian Ebel said in a statement Thursday that “a strong European leisure airline continues to make great strategic sense” but that Air Berlin’s Niki subsidiary “is no longer available for a joint venture.”

Etihad holds 29.2 percent of Air Berlin and has helped keep the loss-making airline aloft over recent years. The merger talks, announced in October, were viewed as part of efforts to restructure the company.

In December, German rival Lufthansa’s Eurowings and Austrian Airlines units reached a deal to lease 38 planes from Air Berlin.