Fast Kitty,
Most vets strongly advise against using sedatives, especially for brachycephalic breeds. Ask your vet about doing a 'fitness to fly' check up.
The weight limit for animals traveling in the cabin is usually around 7-8kg including carrier - check with your airline for specifics.
While I don't like to fly my dogs unless it is absolutely necessary, they have flown around the world several times. They always go in cargo, as they are too big for the cabin - and they have always arrived safely. The key thing, IME, is to take time to train the dog to settle in his traveling crate, and to properly kit the crate out for long distances. Also, whenever possible, fly direct - even if it means driving a long stretch of the journey.
I prefer to use a professional shipper to plan and oversee my dogs' travel - it is more expensive, but the peace of mind knowing I have a pro watching my back is invaluable. You could look for someone in your area from IPATA:
http://www.ipata.com/
The person we have used in the past is in Chicago, so not much help to you - but you could contact this Zürich based pet shipping company for information:
http://www.acepetmoving.com/
A professional shipper will advise you on what is best for your dog, will plan the travel carefully, will help you with paperwork, help you with special needs, etc. A good investment, IMHO.
My dogs can no longer fly (health reasons), so if we have to move back soon-ish we will go by boat. As far as I have googled , Cunard seems to be the only transatlantic line allowing dogs on board. This is not my preferred travel option, as the dogs are not allowed in cabins and must stay in the shipboard kennels the entire trip - much more stressful for them than a 12 hour flight would be. But it may be our only option...
I know how nail-bitingly worrying it is when your doglet has to fly. But rest assured, many of us on this board have brought our dogs over without problems.
Best of luck to you - und gute Reise!