I really hope that some of these links help, I will add more when I come across any & as I said please feel free to add any you find!!

The National Autistic Society gives lot's of general advice / help & they have a super Holidays & Days Out Section HERE.

For people in Scotland Scottish Autism site is full of helpful advice / tips

Manchester Airport has a really well publicised scheme where children with autism can be fast-tracked through security to make travelling easier for them and their families, thread full of info HERE
It seems that most if not all other UK airports offer similar schemes / help too, I've found a few more links that may help, but general advice seems to be, contact the Special Assistance dept at your departure airport a month or more before & they will be able to help in lots of ways.

Gatwick Airport Link, they have also produced a booklet Making Your Journey Easier HERE which may well be worth a read.

East Midlands Special Assistance Link
Bristol Airport Special Assistance Link
Luton Airport Special Assistance Link
Birmingham Airport Link
Heathrow Info Link

Edinburgh has a fab little section that may help even if not travelling from there HERE.

Autism Speaks Guide to the Airport pdf has some really useful info in too.

Travel insurance also seems to be an issue on occasion, hopefully the links below will help;

National Autistic Society offer their own (in partnership)
Staysure
M&S Travel Insurance
Insure and Go

I realise that for many carers / parents funding a holiday may be an issue, there do seem to be a few grants available that may help.
The Family Fund seem to offer grants that can be used at places like Butlins / Haven.
Disability Grants offer advice / links on where you can go for help.
Disability Aid Trust offers financial help / support for older children
HCPT
The Adamson Trust can offer financial grants / help & support
Autism Links site providing links to othere websites that offer holiday help / support to people with Autism

Merlins Magic Wand offer days out at their Merlin Attractions such as Legoland & Sea Life Centres

There's a great system called Boardmaker (it's software and you print what you need). Expensive, but you may be able to access it through autism support or schools. I've 2 autistic grandchildren, who were helped a lot with this, especially for trips and holidays. The fear of the unknown seems to be a big problem, so preparing them with simple images of what to expect was good. There are small, very simple, clear drawings of each step. These can be cut out and laminated. With velcro on the back the pictures can go on a strip in any order. For instance, going to school - a strip by the front door had a clock showing 8.30. then the door open, then a car etc. It helped with toilet training, too. For holidays, once they were used to using the images, the pictures went on a keyring so could be shown in any order. Hope this helps. We've seen a tremendous change over the years, still needing preparation and support but much easier.
http://www.autism.org.uk/visualsupports

Something else I remembered, since the official diagnosis, my nephews school have been very supportive & have offered to allow my sil / bil to take him & his sibling out of school for 1 week without paying a fine & with official approval, so they get away in quieter periods

I really hope that some of these links help, I will add more when I come across any & as I said please feel free to add any you find!!

The National Autistic Society gives lot's of general advice / help & they have a super Holidays & Days Out Section HERE.

For people in Scotland Scottish Autism site is full of helpful advice / tips

Manchester Airport has a really well publicised scheme where children with autism can be fast-tracked through security to make travelling easier for them and their families, thread full of info HERE
It seems that most if not all other UK airports offer similar schemes / help too, I've found a few more links that may help, but general advice seems to be, contact the Special Assistance dept at your departure airport a month or more before & they will be able to help in lots of ways.

Gatwick Airport Link, they have also produced a booklet Making Your Journey Easier HERE which may well be worth a read.

East Midlands Special Assistance Link
Bristol Airport Special Assistance Link
Luton Airport Special Assistance Link
Birmingham Airport Link
Heathrow Info Link

Edinburgh has a fab little section that may help even if not travelling from there HERE.

Autism Speaks Guide to the Airport pdf has some really useful info in too.

Travel insurance also seems to be an issue on occasion, hopefully the links below will help;

National Autistic Society offer their own (in partnership)
Staysure
M&S Travel Insurance
Insure and Go

I realise that for many carers / parents funding a holiday may be an issue, there do seem to be a few grants available that may help.
The Family Fund seem to offer grants that can be used at places like Butlins / Haven.
Disability Grants offer advice / links on where you can go for help.
Disability Aid Trust offers financial help / support for older children
HCPT
The Adamson Trust can offer financial grants / help & support
Autism Links site providing links to othere websites that offer holiday help / support to people with Autism

Merlins Magic Wand offer days out at their Merlin Attractions such as Legoland & Sea Life Centres

From looking at the various links on the NAS Holidays / Days Out LINKS and the websites mentioned above, both large holiday companies such as Butlins & Haven & smaller more local ones offer holidays geared towards families that include someone with autism.

Happy Kids Holidays offer holidays in France & they look a fab company.

Do you dream of a holiday in the sun where:

every member of your family is welcomed and there are no stares and no embarrassment?
the environment is safe and you have been made aware of any dangers?
you've had help planning and preparing for your holiday?
you have someone to turn to if there’s a problem?
you know your requests will be taken seriously, no matter how unusual they might be?
If the answer to any of the above questions is "yes" then happykidsholidays is for you.

Badaguish Outdoor Centre Scotland looks amazing, it has lots of facilities on site & loads more to do nearby for the WHOLE family, it even offers Short Break Respite Care Activity Holidays with 24-hour care.

The Calvert Trust in the Lake District offer warm welcome; accessible accommodation and exciting breaks for schools, groups, families and individuals with their friends and carers. They are accessible to people of all ages with sensory, learning or physical disabilities, including those with the most complex needs for which most outdoor centres cannot cater.

Disability Snow Sport offer week long activity trips to the mountains and snow in the rest of Europe and the USA.

The Thomas Centre in Lincs offer breaks where their aim is to provide holidays that meet the needs of the whole family, not just the needs of the family member with special needs.

Disabled Holidays
A fantastic selection of holidays with plenty of things to see and do for children with autism to enjoy.
At DisabledHolidays.com, we know that looking for the right holiday for a family member with autism can be time consuming and stressful. Finding a destination with appropriate facilities and with staff who are sensitive to you and your needs is a priority

Haven Holidays

Butlins

Center Parcs - advice across the net seems to be ring and ask to speak to their special assistance team.
Other sites that offer help in finding the holiday that suits the whole family are;

HFT 2016 Holiday Information Guide Full of help / advice / links of places to stay

British Institute of Learning Disabilities.Info on Holidays Really useful info / links

The Autism Show in London, Birmingham & Manchester mid June - early July should be a huge resource of useful info / help

Thanks for making this thread, I've got a brother who has autism. Information will come in handy

I have a son on the spectrum and a daughter who I think will be diagnosed to.
We have been on holiday once in 7 1/2 yrs. we went for 7 days. After 2 days we were back home. It was just to much. We have booked a holiday since. But I can led and just could not face it. This yr. I have said maybe to do a long weekend. As he is older. So thank you for this thread.

"Autism Awareness Month"

Alton Towers
If you take your documentation to Guest Services, you don't have to queue for any ride.
Lifesaver.

Thanks for sharing.