You can fly in and out of the United Kingdom with an Emotional Support Animal in the cabin but there are restrictions on which airlines allow Emotional Support Animals, the size of Emotional Support Animals, the type of Emotional Support Animals and which airlines are allowed to fly Emotional Support Animals in the cabin back into the United Kingdom. For example US Airlines allow Emotional Support Animals in the cabin to fly into the US and then fly in the cabin back into the United Kingdom they do have a size limitation, whereas there is a current ban on flying Emotional Support Animals from most other countries and airlines in the cabin back into the United Kingdom. Another example is Belavia Airlines where you can fly your Emotional Support Animal with you in the cabin Gatwick Airport direct to Minsk International Airport but there are size restrictions and only two animals allowed in the cabin on any flight. They do not have a permission to fly the Emotional Support Animal in the cabin back into the United Kingdom. In the European Union you will have little issues (size resitrictions) with flying your Emotional Support Animal with you in the cabin to and from any country in the EU but some airlines do have size restrictions. You must also be aware that each country has their own level of quarantine and you need to abide by all the countries you plan to visit rules and regulations and your Pet Passport must be up to date with all required vaccinations, wormings and other medical requirements. We are currently researching and creating an Emotional Support Animal Flying Certification which will focus on what type and amount of training each type and breed will require to fly safely for themselves and other passengers which we hope to finalize mid-2020. This ESA Flying Certification will involve your Emotional Support Animal being assessed by a certified trainer and then advise training that will be required for travel on the planes in the cabin. Smaller breeds will require little training as they will be in their bag/cage while in flight on floor in front of the seat of you whereas larger breeds will need to show they are trained to be fully in control and safe to other passengers.