Easyjet has cancelled hundreds of preemptive flights up to June 6 due to their IT problems and traffic control restrictions at Gatwick. They are planning on-the-day cancellations too. Destinations affected include Seville, Rome, Barcelona, Bilbao, Geneva, Glasgow, Krakow, Lisbon, Madrid, Milan Bergamo, Milan Malpensa, Olbia, Palermo, Prague, Valencia and Venice. British Airways is continuing with…