French Finance Minister Bruno Le Maire warned that excessive salary demands and strikes by unions at Air France-KLM Group could sink Europe’s largest airline.

“If it doesn’t make the necessary efforts to be at the same competitive level of Lufthansa and other major airlines, it will disappear,” Le Maire said on BFM TV on Sunday. The union’s salary demands are “unjustified” and employees must show “responsibility,” he said.

Chief Executive Officer Jean-Marc Janaillac resigned Friday after…