Both KLM and Lufthanza allow you to bring pets from the UK (via Netherlands or Germany) in the cabin. The pet plus the carrier has to weigh under around 8kg (which should be fine for a small breed). Price is surprisingly minimal - it is a fixed excess baggage charge of around £70 (check with airlines). The pet has to be transported in a carrier which fits under the seat (really only during take off and touch down). There are special soft carriers which have a tent-like squashable roof which will fit under the seat and spring back up. The brand that springs to mind is Sturdibag. Good luck! Btw I was told about the airlines by Doha Vets (who were amazingly helpful) and then checked directly with the airlines in the UK, who agreed with this...