If you are flying with an assistance dog, it is important that you tell the airline when you book your flight. You also need to:
Ask the airline what rules apply for assistance dogs on your particular flight.
Check what rules apply for assistance dogs in the country you are flying to.
Check what vaccinations the dog must have and whether there are any
Quarantine rules for the country you are flying to.
Even if you have an assistance dog, you can get help at the airport from PRM Assistance, which will help you to your seat in the aircraft if you would like that.