I'll join the others in encouraging you to use the wheelchair service - my husband needs it and it really eases the trip through the airport. I would recommend saying that you're unable to use stairsin anticipation of the rare situation where the plane lands at a remote gate - even though you have to wait for the transfer by special bus we've found we still get through immigration etc well ahead of the rest of the passengers. As Katja has recommended, always reconfirm the service directly with the airline a day or two ahead of your flight. I also take a copy of my reservation which shows I've requested this service - have had to use it on one occasion with Emirates when they claimed we hadn't requested assistance. Enjoy your trip, you'll find the airport transfers much less stressful.