LONDON - British Airways canceled more than 1,000 flights after its cabin crew launched a three-day strike Saturday, wreaking havoc on the plans of tens of thousands of passengers just before the busy spring holiday season. Hoping to keep as many passengers happy as possible, BA scrambled to rebook some on other services, chartered planes from rival airlines and drafted in volunteer crew. But it still had to scrap more than half of its 1,950 scheduled flights over the period. Chief Executive Willie Walsh issued a direct apology via YouTube for the walkout, the airline's first in almost 15 years, saying it was a "terrible day for BA." The strike ��" backed by some unions in the United States, Germany and Spain ��" also risked harm to Britain's Labour government before a tough general election expected before June. On Saturday morning at BA's London Heathrow hub, the cavernous Terminal 5 was nearly deserted after some passengers had flown out early to avoid the strike or simply stayed away altogether. But delays were beginning to mount. One man trying to get home to Sweden said he was already looking at a four-hour delay. "Our flight from Dallas arrived two hours late, and now we're waiting to go to Stockholm ��" that flight is two hours late as well," said Bjorn Barka, a high school principal. Michael Clements, a security director for a California-based company, was able to check in for his business trip to Amsterdam but was told it would be an hour before he could check in his heavy luggage. "Not enough people," he said with a shrug. The Eurostar train service between London and continental Europe and Virgin's rail services between London and Scotland were expected to be busy as passengers sought alternate routes.