Lufthansa has been Air India's mentor, helping and guiding it complete all formalities for joining the alliance.
Pilots represented by union Vereinigung Cockpit were holding a strike at Munich airport, Lufthansa's second biggest airport after Frankfurt, from 0800-1600 GMT on Wednesday.
Andreas Lubitz, the co-pilot who deliberately crashed Flight 9525, was once suffering from depression; had confessed to 'burnout'