(Refiles to fix dateline, with no changes to text)

(Reuters) -Lufthansa shares dropped over 4% on Tuesday, more than erasing gains from its capital markets day, as some brokers raised doubts over the achievability of its mid-term targets.

JPMorgan called the airline's goals "ambitious" and said execution risks could mean one or two transition years with limited free cash flow. 

"We are underweight Lufthansa and are yet to be convinced on the equity story and airline turnaround," they said.

Deutsche Bank and Kepler Cheuvreux highlighted structural challenges and a lack of transformational change. A looming pilot strike also added to investor caution.

Lufthansa shares fell 4.15% by 0920 GMT, leading fallers on Germany's midcap MDAX index and heading for their biggest one-day drop since April. The stock remains up over 20% year-to-date.