Do wheelchair-accessible aircraft exist?

At this stage, no. To my knowledge the only option currently is to be moved into a standard seat.

The main obstacle has been the so called "crashworthiness" requirements, where an aircraft seat carrying a person must be able to withstand a crash force of up to 16G without shifting or collapsing.

However, the organization All Wheels Up has developed a prototype solution to allow some wheelchair users to remain in their chairs, and is in the process of lobbying safety regulators and airlines.

• Air Canada - "Wheelchairs and Mobility Aids"

  • Special handling requirements apply to battery-powered mobility aids.
     

  There is no discrimination against you, but you should expect a large wheelchair to go into cargo; rather than becoming a projectile or having larger batteries leak during a crash. See also the second link above regarding "Cargo Door Size Restrictions" and (free) "Disassembly and Reassembly" (which can mean come early and leave late).

  • Special Seating Needs

• one Japanese airline - ANA - "Customers with Walking Disabilities"

  You check-in all wheelchair types and they provide you with the airport's wheelchair (and push you if preferred/needed). Upon your request, you can also use your own wheelchair close to the door of the aircraft. However, please understand that some airport facilities are not allowed to use your own wheelchair due to set conditions. Use of a stretcher is available for customers who are unable to sit upright in an aircraft seat.

• U.S Dept. of Transportation - "Wheelchair and Guided Assistance"

  There's a lot to read on that webpage but some of the most relevant details seem to be:

  • If you travel with a battery-powered wheelchair, you must arrive at the airport 1 hour prior to the normal check-in time.

  • You are entitled to stay in your own wheelchair until you get to the gate. At the gate, your wheelchair will be taken from you. If you cannot walk, you will be transported to your aircraft seat in an aisle chair. Your wheelchair will be returned to you at the gate once you reach your destination.

  • If you need wheelchair assistance to get off of the aircraft, you should know that airlines generally provide this assistance after all other passengers have deplaned.

The website WheelchairTraveling.com provides some additional information about traveling, such as rugs can be more difficult to traverse as can some of the ramps. Also interesting is that your wheels can roll through something, and then when you get swabbed during screening you may not clear.

The simple answer is: everywhere is different and you need to phone each airline you plan to fly on and contact the airport for additional information about their procedures. Arrive early and expect to stay late.

... what is the limiting factor?

Every possible size of wheelchair can't be inspected and certified for flight and an interface made available to secure it. Even Unit Load Devices (aircraft luggage containers) have a fixed number of standard sizes.

Sleeper seats are surely more expensive than cramped economy class but some airlines do offer them. While you say you cannot sit on any other chair, I assume probably you can fly lying down. Some companies like Alitalia will allow you to travel in a stretcher.

Looks like you need a friend or two with you to help with moving between the seat and your wheel chair, and the best it would be if you can spend a short time in a normal seat while taking off and landing. If not, so some rules may exist to work around the requirement of sitting properly if there are medical reasons. May be worth asking.

Other possible considerations beyond crashworthiness as outlined in Ben's answer:

Doors are made only as large as necessary; larger doors bring structural issues, the solutions to which almost inevitably add weight to the aircraft. Passenger doors typically have rounded corners (again, for structural reasons), which means the flat portion of the threshold may end up rather narrow, likely becoming a barrier for some wheelchairs.

There may be issues with the way jetways meet up with the doorway; it may just be due to the way the operator positioned it on a specific flight or intrinsic to the jetway's design. Regardless, there can be a step and/or narrow gap between jetway and cabin door threshold; I've seen it as a tripping hazard, I imagine such a situation might be problematic for a wheelchair to navigate safely.

Economics and profit motives drive airlines to fit as many passengers as possible into the available cabin volume and floor space of a given aircraft at the expense of passenger comfort and room to move around. Most aircraft therefore have very little floor space that isn't occupied by seating, lavatories, galleys, etc.. To offer better accessibility would require an airline to forgo the revenue equivalent of perhaps one or two seats per aircraft, a reversal of recent trends.

It is extremely technically difficult to make jetliners be "roll on, roll of" for power chairs. That is not likely to become possible to improve anytime soon, and it is why airlines are exempt from ADA.

Take the train

Amtrak is subsidized for a number of policy reasons. One is to enhance accessibility for folks like you.

If your location is Buffalo, you have reasonably good access to the national system. Pennsylvania and West Virginia are hard, but you have decent access to the East Coast and South, and the west is your oyster. In particular, going from Buffalo to Los Angeles,

• you would be on the Lake Shore Limited, the east's fastest overnight train. Midnight departure out of Buffalo, sleep through northern Ohio, and a 9am arrival in Chicago. Spend the day shopping (you're blocks from the Loop).

• Then a 3pm departure on the Southwest Chief, the fastest overnight train nationwide. It uses a mountain-avoiding straight-shot on the "Santa Fe Racetrack" route, so it is much faster than the southern, central or northern routes. The 43 hour night-day-night run puts you into L.A. between 8am and noon.

Accomodations exist both in coach and sleepers. The eastern trains have a high deck, and use either high or low level platforms. At low level platforms, they will use a "wheelchair lift" to get you to deck level. The corridors are too narrow to reach the whole car, but you will be able to get to the ADA sleeper compartment or a chair tiedown area in the coach, and a bathroom.

The western trains (and Auto Train, and Capitol Limited) use low-deck Superliners, which all use low-level platforms and a very simple ramp. You will be able to move about the lower deck of the car somewhat. The attendants will bring you diner meals or snacks from the cafe car.

In sleeper cars, dining car meals are included. Coach passengers can pay for dining car meals a-la-carte. Both can buy 7-11-tier microwave fare from the cafe car. The cafe is priced a bit above 7-11 and far below airlines. The dining car is priced like Applebee's.

Let me give you the standard speech about late running that I've been giving for 25 years. A very, very long train run has many opportunities for small delays, and all those delays stack because Amtrak doesn't build much recovery (sitting around) time into their schedule. You just have to plan for it, relax, and don't worry about it. If you can't settle for that, then Amtrak is not for you clearly, you haven't flown much in the last 10 years...

I travel Amtrak a lot, and have seen some whopping delays for wild (but reasonable) reasons. My worst, however, was actually on JetBlue.

In my experience, Amtrak often tries to work alternate transport during long delays. When there's a viable choice, I find it's usually wisest to stay with the train and wait it out. The railroads are very, very good at keeping their track open, and Amtrak trains are modular and single broken engines or coaches can be set out or simply carried along inoperative.

I have read your question carefully, and I will answer each question about you. hope this helps.

1. Whether an electric wheelchair can be carried on the plane depends on your battery specifications and brand.I have reviewed the regulations of several airlines. Lithium batteries below 6Ah can be brought on the plane like luggage.At the same time, you must make an application with the airline 24 hours before the plane takes off.

2. On the plane, personal wheelchairs are not available. Whether it is an electric wheelchair or a manual wheelchair. The airline has a dedicated transfer wheelchair. All wheelchair users must use the airline's wheelchair on the plane.

3. These restrictions on airlines are for security reasons. First of all, the requirements of the battery specifications are to prevent the battery from leaking and exploding.Secondly, the use of special wheelchairs for people with physical disabilities is for the safety of the guests.