Germany's Air Berlin said on March 27 that it bought Dusseldorf-based airline LTU for 140 million euros (US$186 million) in cash to expand the business.

In addition Air Berlin will assume between 190 million and 200 million euros of LTU's debt.

"Through this transaction, the Air Berlin group will become the largest airline in the most important German source market," the company said.

LTU will remain a legally independent company within the Air Berlin group, with its own management, and will retain its own name "in the foreseeable future," Air Berlin said. The acquisition makes Air Berlin the fourth largest airline for European traffic behind Ryanair, Air France/KLM and Lufthansa, the company said.

Separately, Air Berlin agreed to buy a 49 percent stake in Switzerland's Belair Airlines, a unit of the Hotelplan group. Financial details were not disclosed.