Can anyone who understands claustrophobia/agoraphobia help me?

You could try systematic desensitization, but since your time is short before your flight, better options might be EMDR or hypnosis. Many therapists list conditions they treat and their methods of treatment. EMDR.org lists qualified EMDR practitioners and information about EMDR. Also consider seeing your doctor for antianxiety medication like Valium or Klonopin to use on your flights. You don't want to have a panic attack while you are "trapped" on an airplane for 22 hours. Always remember to breathe and good luck.

I definitely agree about the writing. I suffer from severe anxiety attacks, and have recently started doing more writing, and I feel it really helps. Other distractions help me, too. If I start focus on getting a panic attack or that I'm feeling a certain way, it usually becomes a self-fulfulling prophecy! Got to stop it in its tracks! Stay busy (bring a book, some tunes, a notebook, crossword puzzles, etc.), and also give yourself positive self talk. Just for the sake of putting your mind at ease, you may want to check into some meds, as another writer suggested. I currently use Xanax on an as-needed basis. It is a great help. It's something you want to be careful with, as you don't want to get hooked on it, but it does get me through the tough times. Don't worry, you will be great.
You know what else has helped in the past? I think we are so worried about losing control, and hiding these feelings from others, that it makes everything worse. I've found in certain situations (like at an appointment or whatever), if I feel an attack coming on, I am open about my feelings. I've been in places before where I've told the person that I experience panic attacks, and am feeling a bit edgy. SO many times, they open up to you about their experiences with panic or anxiety or situations they have had, or a loved one who has it. It's very common! If you are sitting by someone on the plane that seems friendly or you get to chatting, tell them about your worries about the flight, etc. Depending on the person, they could turn out to be a great support! Just an extra idea.

Hypnotherapy and/or EFT are good ways to deal with any phobia. I use a combination with my clients because EFT gives then a self help technique that allows them to address their anxieties wherever they are sothere isn't a concern of "it worked in her office but will it work when I'm on the plane?" I would recommend seeing a hypnotherapist for a personal session rather than using CDs if you can because you will get a better result for you. If you don't have time and you need a fast solution then go to the EFT website and download the free manual. It may seem strange but follow the technique and you should notice a difference. If you type in EFT and free manual then you should find it.

If you like to read....get a nice, big book, with a topic that really interests you....or take some magazines....crossword puzzles....anything that you enjoy, that will keep your mind off of your anxiety....

Also, I saw a special on television, and for people who have a fear of flying....Dr.'s can prescribe beta-blockers....it will help keep your heart rate from sky-rocketing (because your fear isn't really flying, it's "what if I have an attack, and make a scene in front of everyone") ...talk to your doctor...

I have issues with inclosed spaces and crowds sound familar. What I found out by accident when getting on the plane ask the stewardes for a glass of water. I took 2 motion sickness pills, 2 extra strength tylonal, and 2 st. johns wort. I felt really good, it can make you a little goofy but it helps get you through the flight and they are all over the counter stuff.