bipolar service dog

flying with my small service dog?
7 lb maltese is a therapy dog. I have a proscription from a therapist and from my doctor. She has a service jacket and it says therapy dog. I have her health certificate, tag and proff of shots. Will there be any problem having her on my lap on the flight/ She cannot do her job if she is in a carrier under the seat.
She brings me out of panic attacks, keeps me calm,, licks me if my blood sugar goes too low and gets my attention so I can take care of it immediately. I am diabetic on insulin, have bipolar and panic disorder as well as anxiety disorder.
Make the arrangements in advance with the airline; in the US service dogs are just fine on airplanes but they do need to know in advance that you are travelling; for example, some seats on some smaller jets would be better suited for a passenger travelling with a service animal than other seats would be. There may or may not be a fee for transporting the animal. I believe the animal needs to be restrained (in the carrier for a dog that small, or some other way to restrain them) for safety reasons during takeoff and landing, just the same as people need to be wearing their seatbelts during those times. But the airline can help you through all the specifics.