Boarding and disembarking
If your pre-planning has worked then all your needs should be met in accordance to your booking.
If you use a wheelchair, you need to be aware of what will happen to it during the flight. It may be possible to store a manual, folding wheelchair in the passenger compartment if suitable accommodation is available.
It is more likely, however, that your wheelchair will be stowed in the luggage hold; this would certainly be the case for all powered wheelchairs.
In either case, airports and airlines should allow you to remain in your own wheelchair to the door of the aircraft. They should also deliver your wheelchair to the same place upon arrival at your destination. In the case of powered wheelchairs this may not be possible. If, for safety reasons, the wheelchair needs to be stowed in a particular way in the aircraft hold, or at airports where wheelchairs have to be lifted up and down stairs at the gate and staff would be at risk, the airline may not be able to allow you to remain in your own wheelchair.
Make sure you have any necessary medication in your hand baggage and check that you have packed enough to cover any delays to your flight.
If you require the use of an onboard wheelchair then this should have been recorded when you made your booking.
If you have a sensory impairment, the airline staff should make themselves known to you and should offer appropriate level of assistance during the flight. For example, they should explain the emergency procedures and they can assist with food packaging.
If you have breathing difficulties and require supplementary oxygen for the duration of the flight, the airline will provide on board oxygen. Some airlines will make a charge for this service. But you cannot take your own oxygen. If you need oxygen only in an emergency there will be no need to order an oxygen cylinder. The standard, emergency oxygen which is provided by all airlines will be available.
At the end of your journey
If the airline meets all your needs in accordance with your booking then your journey should be as comfortable as anyone elses. But if things do go wrong, it is worth notifying the problems promptly to the relevant bodies.