Scandinavian Airlines (SAS) has been forced to cancel all its Tuesday morning European-bound flights out of Copenhagen because of a pilots' strike.

About 270 flights have been grounded, stranding thousands of passengers. Normal service is expected to resume after noon local time .

SAS was also forced to cancel at least 80 flights out of Oslo Monday when a number of pilots called in sick.

The Danish pilots are protesting SAS plans to re-negotiate their contracts which the pilots' union says will mean possible layoffs and worse working conditions.

Some information for this report was provided by AFP and AP.