It depends on the airline, airport and the configuration of the ramp to the side of the plane. Sometimes you can drive right up to the side of the cabin and other times you can check it in at the gate. You can also check it in at the curb and let them push you around with a wheelchair. They do have wheelchairs for guests that cannot walk and want to go potty or exploring shops and restaurants. The aisle chair has no arms and is very skinny for going down the aisles. Anything medical is not counted as luggage so put all of granny's depends, for example, in one bag and say that it is all medical. That way you get one bag free if it is all medical supplies.
Be advised that wheelchair service may mean sitting for over an hour in LAX, asking numerous people for help and then watching others being helped first. Some airports like Dallas have carts that you set in and are driven around the airport, like busses. Cute little golf carts. Some airports I have gotten excellent service and other times like LAX made to feel like a dolt who is wrong and it is my fault there are no chairs. Other airports make you feel special.
Check online for where your plane will take off. Most airports will show where food, restrooms and shops are.
www.seatguru.com will show you the seating charts so that you do not get stuck in a seat not for you. Some seats are fine for skinny people and others are a bit cold. They do have extension belts for pooh sized people like me. DO NOT expect the armrests to go up as I have been on 4 flights in 2005 and 4 flights a couple of weeks ago and not one seat armrest went up despite being marked handicapped. If you need the arm to move then contact the airline and do not rely on their charts.
See the tears and dent in thick steel skeleton of my suitcase. They can and may disassemble a
scooter or chair to make it fit. Take everything you can with you on the plane. Sue said she takes a laundry bag then removes parts like baskets, doodads, cup holders, cane holders, foot rests, etc and immediately puts them in the bag so she does not loose them.
Dont for get the gum for your ears, chewing helps. Ask for help if you need it. And for me turbulence is almost as much fun as an earthquake or a roller coaster. I think of the song Hawaiian Roller Coaster from Lilo & Stitch movies. It got pretty bad and I just closed my eyes and dreamed of the Bobsleds and other roller coasters. Not scary when you are thinking of roller coasters lol.
Pack snacks just in case. In my southbound flight to San Antonio the plane was delayed as they dried the carpets. Because my flight was delayed the next flight was delayed so the Austin bound people had to haul rump across a very very very very large airport and nobody was out there directing traffic or helping guests. I had on me peanut butter, cereal, candy, and almonds going in and a loaf of bread, almonds, and peanut butter and cereal going out.