British Airways is expected to announce which of its flights may be cancelled because of a strike planned by cabin crew for next weekend.
The dispute is over reduced staffing levels and pay at the airline, with the first strike due to start on 20 March.
Meanwhile, a Downing St source refused to confirm whether Gordon Brown has spoken to the Unite union.
The strike is due to last for three days, with a second four-day walkout due to begin on 27 March.