German flag-carrier Lufthansa said it would cancel two-thirds of its Friday flights after a cabin crew union announced a 24-hour stoppage at six major airports.
American Airlines and United Continental must face trial over a lawsuit in which the lease holders of the World Trade Center allege that lax security allowed hijackers to destroy the Twin Towers on September 11, 2001.
German flag carrier Lufthansa on Tuesday cancelled over 200 flights at its Frankfurt hub, Europe's third busiest, as a union chief threatened to hit every German airport with a 24-hour strike on Friday.
A Qantas Airways pilot failed an alcohol test after being removed from the controls of a passenger flight just minutes before take-off over concerns she had been drinking.