As a whole, the World Lufthansa is made of two words: 'Lupth' and 'Hansa' which are two Sansrkit words meaning Disappearing swan or a crane (bird).
The logo was designed by Dr. Otto Firle and when he designed it he was thinking of a swan or a crane(bird) and "free as a bird" so that's how he came up with the logo.
Briefly
When an aeroplane service first started in Germany, the aircraft they employed in service were pure white, resembling huge white swans. When these aeroplanes would fly into the sky and grow slowly smaller and disappear, they would look like swans disappearing into the heart of the sky. In Sanskrit, the word that could describe them was lupth-hansa, or the hidden swan and that's the correct meaning.