Insolvent German airline Air Berlin AB1.DE is continuing talks with easyJet EZJ.L on Thursday, a spokesman for Air Berlin said, without saying whether a contract was expected to be signed with the British airline.
Air Berlin said that Lufthansa would pay 210 million euros for Air Berlin assets, enabling it to repay a 150 million credit from the German federal government that had allowed it to keep flying.
"Today will be a milestone in the history of Lufthansa and Air Berlin", said Spohr in Berlin ahead of the expected official announcement that a formal deal has been agreed between the airlines.
Spohr said that both airlines will sign the agreement later in the day in Berlin. News of the deal pushed Lufthansa shares up more than 3 per cent to their highest level in almost 17 years.
Lufthansa will purchase Air Berlin subsidiary Niki, a low-priced airline based in Austria, as well as Air Berlin's regional subsidiary Walter, which now flies under the Air Berlin brand.
"We will only be able to breathe when the Commission has finally confirmed the transaction", Air Berlin boss Thomas Winkelmann said in the company's statement.
Lufthansa would reportedly take over 81 planes from Air Berlin for its main brand and lower-cost Eurowings operation.
That sum includes investment in new planes, for which the board freed up 1 billion euros of funds last month, the purchase price and the costs of taking on new staff.
Germany's second-largest carrier has since been negotiating with potential buyers for parts of its business.
The group's finance chief Ulrik Svensson had said in August that Lufthansa was interested in helping to shape the Italian aviation market but was not willing to take over the struggling national carrier in its current shape.
Lufthansa shares were up over 2.9%, which was the highest mover on the DAX market index in Germany in Thursday morning trading.