Germany’s richest man wants to buy more Deutsche Lufthansa AG shares after investing a chunk of a fortune made in logistics into Europe’s biggest airline.

Klaus-Michael Kuehne is looking at expanding his 15.01% stake in Germany’s flag-carrier airline, according to a filing from Kuehne Holding AG late Tuesday. The logistics mogul earlier this year overtook the German state as the biggest shareholder in the carrier.

“Our interest in Lufthansa is unbroken,” the 85-year-old said in the statement. “I recently had a constructive talk with the chairmen of the supervisory board and the executive board. We therefore intend to acquire further Lufthansa shares when the opportunity arises.”

Klaus-Michael Kuehne

Kuehne, who also expressed interest in taking a board seat at Lufthansa, is worth $31.3 billion, according to the Bloomberg Billionaires Index. He is honorary chairman and majority owner of Kuehne + Nagel, the world’s largest sea-freight forwarder.

While the magnate hasn’t commented publicly on his overall vision for building a Lufthansa stake, several major shipping companies are branching out into commercial aviation, especially carriers with cargo operations like Lufthansa. And logistics companies have enjoyed soaring profits over recent years amid a freight boom, leading several to reinvest those earnings into airlines.

Kuehne’s holding company also owns a 30% stake in German shipping firm Hapag-Lloyd AG, a company that until now hasn’t made an attempt to acquire aviation operations. Lufthansa’s cargo division operates a fleet of large cargo aircraft and also makes use of the belly space in the passenger division’s jets.

French logistics giant CMA CGM SA in May agreed to acquire a stake in Air France-KLM, while container giant MSC Mediterranean Shipping Company SA has made a joint bid with Lufthansa to acquire Italia Trasporto Aereo, known as ITA, the successor to failed carrier Alitalia.