Thousands more travellers faced further delays and cancellations despite pilots returning to work after their first ever walkout at the airline.
A landmark strike by British Airways pilots entered its second day on Tuesday with more travel chaos - and no end in sight to the long-running dispute over pay.
The 2.55pm flight from Gatwick has been cancelled on both days, as well as the return flights scheduled for 8.10pm.
The spokeswoman said: Unfortunately, with no detail from Balpa on which pilots would strike, we had no way of predicting how many would come to work or which aircraft they are qualified to fly, so we had no option but to cancel almost 100 per cent of our flights all over the world.. And in addition to pilots being in the wrong place, BA said there was severe disruption to rosters for its 4,000 cabin crew.
"Every single flight movement also has to factor in detailed planning, including engineering checks, maintenance, catering, fuelling, baggage loading, cargo and cleaning".
"British Airways needs to start listening to its pilots and actually come up with ways of resolving this dispute". We understand the frustration and disruption Balpas strike action has caused our customers.
BA has offered a salary increase of 11.5 percent over three years, which it argues would boost the annual pay of some captains to £200,000 ($246,000 or 220,000 euros).
BALPA estimates that the 48-hour strike is costing the airline a total of £80 million but BA has yet to give an estimate.
BALPA General Secretary Brian Strutton commented: "Surely any reasonable employer would listen to such a clear message, stop threatening and bullying, and start working towards finding a solution".
Adam French, Consumer Rights Expert at Which?, urged BA to inform its passengers of their rights to claim compensation and alternative flights.