I'm claustrophobia just like you. Everytime I fly, I always try my best to get an aisle seat. I try to book way early and I avoid flights without available aisle seats when booking. Getting an aisle seat is my #1 criteria when booking a flight.
I had an episode of serious panic attack years ago when I was put on a plane that only seats 18 passengers. The plane was so small that I couldn't stand up straight in the airplane. (And I am only 5'5"). The plane was on the runway getting ready to take off and I had to ask them to stop the flight so that I could get out. I couldn't breathe and I thought I was going to die. They put me on a second flight that seats 27 people. It was still a small airplane but it made a huge difference and I was able to manage my claustrophobia in that one hour flight.
One tip that I can offer you is that that suffocating feeling can come from no airflow around you. So as soon as you get on the flight and get seated, (And hopefully with an aisle seat) open the air vent so that air is blowing at you. At the same time, as soon you enter the plane when the flight attendant greets you at the entrance of the plane, ask him/her to give you a cup of ice. Explain to him/her that you are claustrophobic and that cup of ice will help you manage your fear. Once you are seated, hold that cup of ice in front of your nose so you can breathe in the cool moist air. It helped me tremendously in calming down that feeling of being stuck in somewhere.
Good luck and try to focus on planing your travel experience in the US and happy thoughts during the flight.
Although I am claustrophobic, I love travel and I fly all the time. There is no way I will let it stop me from visiting all the cool places in the world. :)
Have a great trip!