British Airways has been forced to ground 1,300 flights after talks to avert the walkout by cabin crew staff failed.
Analysts are estimating the grounding of the flights from Heathorw and Gatwick next Tuesday and Wednesday could cost the airline up to £30 million.
The cancellations are set to affect 154,000 passengers scheduled to fly from Heathrow and on domestic and European flights from Gatwick.
Meanwhile, HotelConnect has vowed to waive cancellation charges for customers affected by the BA strikes.
The bed bank said customers cancelling 48 hours before arrival will be able to do so free of charge, while it will encourage hoteliers not to charge for bookings cancelled within 48 hours.
Meanwhile, Eurostar has seen a significant increase in bookings for next Tuesday and Wednesday as business travellers look for alternative travel options.