I prefer (1). (2) could be taken to mean that you are worried about yourself as opposed to other people (which I think you don't mean). Even in (1), the first sentence is technically ambiguous as to what "when the plane takes off" modifies, but the meaning you explain makes more sense and is likely to be assumed, I think.
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navitasanwhen the plane takes off.That second use of "the plane" is repetitive. It would be better as: when it takes off.
navitasanAre these sentences correctYes. 1) is better.
navitasan'when the plane takes off' does not modify 'I am worried'. It postmodifies 'my reaction' and ''myself'.That's how I would read it, yes.