Do not book through Thomas Cook. They may use a third party like RyanAir to book your flights, and those bookings commonly fail (as admitted to many times by many Thomas Cook agents and RyanAir agents). They will not, however, tell you when this happens. Only when approached will they tell you it has failed and that your flights now cost more, as they failed to book them when paid for. They will absolve themselves of all responsibility, despite having their terms and references pointed out to them on several occasions. If you then have any problems with flight verifications or check-ins using RyanAir, you will not be able to seek help from either customer service. It’s impossible to know for sure if my flights are finalised, or to add the luggage that Thomas Cook forget to add when rebooking the flights that they failed to secure due to incompetence. Do yourself a favour and spend the little bit extra to just book everything yourself independently. Thomas Cook will take your money and do less than the bare minimum to assist you if anything goes wrong.