Short answer is flying is out the question.
My wife has dementia and Alzheimer's. The airline (ryanair) requires a letter from the doctors saying she is OK to travel. I asked the doctors for a letter and they said they could not issue one as they would be liable for the cost of diverting the plane if my wife started to "play up" during the flight.
That question is impossible to answer as it very much depends on the person with the dementia and their symptoms.
I fly medium haul with my wife and she has to be kept in close contact as, whilst she is generally co-operative, she can get confused and wander off if not watched. Airports can lead to stimulation overload, which may cause issues for some.
The UK airport we use(Belfast Intl) issue hidden disability lanyards which help with our transit through the airport. The airport at the other end doesn't have such a system.
I have to say that my experience with the airline I use is not the same as that which Alex54 had with his. The company I used just removed seat selection from our options if we wanted to declare the disability but said we were free to pick our own seats if we didn't. I guess you just have to check with the airline.
If I was concerned about the possibility of a major incident I wouldn't consider foreign travel by any means.
Hello, @Smd1305, and welcome to Talking Point. I am sorry you have needed to find your way here but hope it will be helpful for you.
If you can be patient with me, I will post some links that might be useful. This is a topic that comes up from time to time on Talking Point. It's not an easy answer, as everyone is an individual and what you are able to manage, will vary widely.
My mother, now in a care home and either in later middle stages or earlier later stages of Alzheimer's, has not been capable of any sort of real travel for at least seven years; short car journeys are now all she can manage and those only when necessary for doctors' appointments. She doesn't mind riding in the car but getting her in and out can be difficult. She is physically quite well, apart from some arthritis, but her visual impairments (both from physical problems and the dementia), inability to process verbal directions at times, and so on, can be challenging. She also gets easily confused and overwhelmed in situations such as a busy doctor's surgery. She has no patience and cannot wait easily for an appointment. She goes to the toilet frequently, and is also sometimes incontinent, so that entails taking a lot of supplies and spending a lot of time in the toilet and feeling nervous about accidents. These appointments tire her a great deal and that can make her irritable and angry and aggressive. You get the idea.
I would urge you to think the situation through carefully, whatever you do. I wouldn't attempt a long haul flight with a person with dementia, even in early stages, but others would and have. As above, I'll post some links for you in a moment.
If you are comfortable telling us more about the situation we might be able to offer more specific advice, but no pressure.
I might read that first as it is comprehensive and may address many of your questions and concerns.
I hope something here is helpful for you. Please don't hesitate to post and ask questions here on Talking Point. There is a lot of experience and advice here. I also find the publications from the Alzheimer's Association very helpful and you may want to have a look round when you get a chance.
My experience is a bit out of date now as my husband died two and a half years. I took him on short haul holidays until around a year before he died. I did declare his dementia but, like Pete, I didn't experience any problems with the airlines. I used airport assistance and we used a wheelchair as the distances were so great in the airports. I always found the assistance provided was excellent and could not have done it without that. That was especially true at the security area. My husband was taken through by the member of airline staff and they waited for me to come through the scanner so that I could assist them. For our last two holidays by plane I took a carer with me.