This is not the best place to discuss the madness of the stockmarket.
www.fool.co.uk is a better place.
The drop should however be put in context to the massive rise from around 150p to 720p over the last 3 years. The current price is 3 times the bottom and about 2/3 of the top.
Before it started to rain so much demand in the UK was very soft with more summer offers than ever before. Ryanair are bringing out some quarterly results in the morning and easyjet on the 6th August. These will show how much the profits have suffered to keep the planes full.
The price of airline shares is very voliatile and it is a very dodgy place to put your money. Having said that you can make plenty if you wait for the next bottom. It climbed for over 2 years and has been falling for only 3 months. I think it has at least a year of falling before the next rise.