BEIJING, Dec. 3 -- Pilots at Lufthansa started a two-day strike on Monday in an ongoing dispute over retirement benefits. The strike -- Lufthansa’s ninth this year -- has cut its operating profit by millions of euros. Let’s take a look.

The strike is Lufthansa’s ninth walkout this year and it’s caused almost half of the airline’s 2,800 flights to be cancelled. The pilot’s union began a two-day strike on Monday after failing to reach an agreement with the airline over early retirement benefits. Eight strikes have already wiped 160 million euros off Lufthansa’s profits. This latest action could add millions more to that tally. And affect 150,000 passengers. "It is very inconvenient for all of us and when you want to go on holiday somewhere, it spoils everything." said Elfriede Bretagne, a passenger of Lufthansa.

Germany’s largest airline wants to phase out its early retirement plan, something the pilots strongly oppose. They’re currently able to retire at 55 and receive up to 60 percent of their pay before full pension kicks in at 65. Lufthansa says it has made concessions, including giving pilots a 5% pay rise. But the airline won’t budge on the issue of retirement. The union says the parties simply can’t agree on the main issues.

"They don’t want future colleagues to receive any more benefits at all and we say that we cannot support this. We are prepared to contribute to cost reductions, but we are not prepared to sacrifice the entire system for those who joined after us." said Hoerg Handwerg, a member of Lufthansa.

The costly strikes has seen the carrier lower its profit guidance for 2015 for the second time this year.Joe Rundle from ETX Capital says that can’t go on for much longer.

"People who are booking business travel around Europe or long-haul are just going to stay clear of them at the moment and it’s damaging for the brand beyond those numbers of 160 million, so I think they will reach some settlement. It’s just that they don’t want to bow down to the pressure because the airline industry is incredibly tight." said Jo Rundle, the head of trading ETX Capital.

Lower oil prices may help ease the pain a little. But continued industrial action won’t do much for Lufthansa’s growth plans. It wants to expand its low-cost operations to compete with budget carriers and its Gulf rivals.