I've had one or two episodes where I've had irrational anxiety on a plane. I think it's probably similar to what you describe. Sometimes before takeoff I feel like my neck is tightining up, it's hard to swallow, and the more I dwell on it, the more intense it gets. I'm not scared of anything in particular, it's just a feeling of not being in control. It's just an irrational attack that builds on itself.

I've found that closing my eyes, taking deep concentrated breaths through my nose and out my mouth will help. It's not an immediate fix, it takes a minute or two, but I've found that the mind has incredible power over the body. You just have to convince yourself that you can stop it, and it works.

Note: I have absolutely no fear of flying/crashing. I can enjoy windy takeoffs/landings and severe turbulance worry free. This is a different kind of sensation.

Hope that helps a bit.