Hi there!
Just wanted to say I admire you guys for not letting disability get in your way of enjoying travel!!!
I've seen great and not so great behaviour from both pax and crew in this respect... also, as you have flown on a US airline (CO) you'd probably have had this high standard as they are very strict with US law relating to treatment of passengers with disabilities onboard. Some airlines in other parts of the world are catching up but it's a slow process.
A few tips from me to make things easier for yourself (and you probably already know these, but, here goes)
Check with the airline when booking if they have any aircraft equipped with an accessible toilet. On Airbus especially, these are two lavatories side by side with a moveable wall between them to convert into one big access bathroom that you can push an aisle chair into, rather than trying to transfer your wife through a small folding door into the lav (I'm not sure what your personal situation is and whether this is even relevant, but SO MANY passengers I've spoken to have been totally unaware that some planes even have this available) SeatGuru can be a good resource to check out the seating plans and see where you might be most comfortable. Obviously exit rows are a no-no but somewhere easy to get in an out of shouldn't be hard to find. Also, check if all the aircraft in the fleet have moveable armrest, or only some rows. This can be really handy and make things much easier. Believe it or not some check-in crew can be clueless as to this sort of thing so might not give you the best seats in this regard.
Let the airline/crew know what you do and don't need. We're not supposed to make assumptions about your wife's ability and therefore all we can really ask is "How may I best assist you?" If you need us to help, great! Let the airline know when booking & again during checkin/boarding. If you don't need any help, even better. I prefer to let the family get on with it if they are comfortable with that, rather than getting in the way and making things even more stressful.
Some airlines have specialised equipment onboard (e.g. slide board for transferring between chair and seat, Johnny belt to support a passenger who has difficulty standing upright, torso support that's used with the regular seatbelt are just a few examples.)
Qantas have a specially-designed lifter to transfer a passenger from their own chair to the aisle chair and seat if needed, it's meant to assist one or two ground crew rather than needing a whole bunch of people and to make it safer and more comfortable for the passenger as well. All these things might seem obvious to the average passenger but unless the airline or traveller communicate sometimes it ends up in a situation where the crew don't want to ask/assume and the passengers might not tell us what they really need.
When it comes to mealtimes, you can order special meals on some airlines but I think it's always a smart idea to BYO for your circumstances. Dcotor's letters (if necessary) and anything needed for a long flight... check also if you get an extra baggage allowance and what the procedure is regarding transfer from wheelchair to aircraft (can your wife use her own chair to the door, or is it taken at check-in to be loaded, for example- often an issue with low-cost airlines to save time)
I guess this is all probably old news to you but please know there are many crew out there who want to help you the best way they can but often just don't know how... I think the most important thing is for each side to just communicate as much as possible with the other, and from your side, allow the crew as much time as possible to do things that you need, as you mentioned during service times things can get very busy. If you have a rough idea of when you might need help to say, take your wife to the lavatory (using the aisle chair) give as much notice as you can so the crew can give you their full attention. That way neither side gets stressed out or feels rushed and can give you all the help you need (and none that you don't
If there's anything else you think of that you want to know, fire away!! Hope this helps and happy travels
