The two unions called the walkouts in a bid to pressure for pay raises after a wage freeze instituted in 2005.

A spokeswoman for the airline said further cancellations were planned for the second day of the walkout, on Wednesday.

The airline, which is in merger talks with British Airways, announced last month that it would create a new airline to handle its short-haul and medium-haul routes in an effort to tackle challenges brought on by the economic downturn.

The carrier is also planning a hiring freeze, a company-wide wage freeze in 2010 and 2011 and lay-offs of all cabin attendants older than 55.