Flight attendants of German carrier Lufthansa at Frankfurt Airport went on strike early on Tuesday, the cabin crew union Ufo said. The action at Germany’s busiest airport started at 4 am (0300 GMT) and was due to last until 11 pm, a union spokeswoman confirmed. Some 600 flights were expected to be cancelled due to the industrial action, according to the national carrier, affecting 70,000 passengers. Lufthansa cabin crew at Munich Airport were set to strike from 4 am to 11 pm on Wednesday. Lufthansa estimates that that strike would result in 400 flights being cancelled and some 50,000 passenger…