In the old days at BA, one used to be able to pay for a hostess to accompany one for the entire duration of the flight, from check in through to baggage claim. I doubt that such a facility exists any more. On the assumption that you either wish to do so or must travel on your own, then one of the better carriers would be the obvious choice, BA springs to mind. I would avoid the connection in New York to Syracuse. It may be that you would have to change airports from JFK to La Guardia, which is not that fun at the best of times. Futhermore, I think that I am correct in saying that you would have to collect your bags in New York and then check in all over again for the internal flight. The USA has no transit system for passengers as such.
I would also suggest that you travel in the best class that you can afford and at the least, let them know in advance that you are a nervous passenger. I would not be too cavalier in telling them that you are autistic otherwise you might end up having to provide a doctor's letter or perhaps have to comply with even more stringent requirements.
Someone very close to home who works with aspergers and autistic people suggests that it might help if one had a series of flash cards. Each card would take one through each precise stage of the traveling continuum. The cards could be as detailed as the person traveling would feel comfortable with. For example..
Security Check.
Liquids in plastic bag.
Expect to remove belt.
Expect to remove shoes.
Computer in separate box.
Walk through gateway.
Expect to be searched if alarm sounds.
Smile at security guards.
(Not an inane grin of course!)
On board.
Drinks service.
Take several cans.
Meal service.
Make choice.
Head for toilet before trays taken away.
Whatever and whatever and so on and so forth.....
The cards can be as detailed as one wants and can cover absolutely every aspect of the flight from check in to exit at destination. All one needs to do is to sit down with a friend who has flown fairly recently and armchair fly the scenario with him until the detail of the pre flight programming is to one's satisfaction.
Must second PAXboy's sentiments and wish you the best of luck with what could well be a very daunting prospect.
