London, England (CNN) -- British Airways took out full-page ads in newspapers Tuesday saying it managed to fly almost all of its routes despite a strike this week by the union representing its cabin crews.
"We are keeping the flag flying," declared the ads, which said the airline flew to 85 percent of its long-haul destinations and 100 percent of its shorthaul destinations on Monday, the first day of the five-day strike.
It promised to fly a similar schedule Tuesday.
"While the strike means we may have to reduce the number of services each day, we will fly the majority of our customers to where they were booked to go," the ads said.
Destinations don't always translate into flights, however. A BA spokeswoman said the airline flew 60 percent of its longhaul flights Monday and more than 50 percent of its shorthaul flights.
Advice for British Airways passengers
In all, more than 70 percent of the passengers booked to fly with BA on Monday were able to take their flights, the spokeswoman said, something she attributed to a contingency plan that includes leasing planes and crews and placing passengers on other airlines.
As for Tuesday, she said, "Today has got off to a good start."
The spokeswoman would not say whether any union members had crossed picket lines.
British Airways remains "open for talks," the spokeswoman said.
The strike is the first of three scheduled to take place over the next three weeks in a dispute between the airline and Unite, the union representing 95 percent of BA's 15,000 cabin crews.
Unite is upset with the airline over pay and working conditions, including BA's plans to reduce the number of cabin crew members on some flights. BA says it is a cost-saving measure, but the union says it will help to damage the BA brand.