Because England is technically an island, this country has strict laws and no dog can enter the country IN-CABIN unfortunately. Only cargo, which means underneath the plane. Well, that’s tricky for me because french bulldogs are also banned from being in cargo. If you have a snub-nosed breed you need to fly into a country in the EU (France, for example) and travel to England on the channel/ferry.
But for those dogs who are not brachycephalic (flat-nose) breeds and can go in cargo, you can fly directly from US to England on United + British Airways.
If you have the means, another option is Jet Pets (based in Los Angeles). They can help you with travel arrangements for your pet to almost any international destination, customs and take care of overnight accommodations, if needed, for your pet.
Once you have the airline chosen and tickets booked, make sure you have all your forms. Head to the official USDA page to print out forms etc. For England, your pup needs an ISO compliant microchip (15 digits), rabies vaccination, health certificate from accredited vet, stamped by USDA office and finally, a tapeworm treatment within 5 days of traveling.