Hi. I'm online and happy to answer your question today.
The dry air and cabin pressure will not increase your risk of having a narrow angle glaucoma attack so you can continue with your travel plans is peace.
I would,however, counsel you to go ahead with the laser peripheral iridotomy for your narrow angles. This is, in the scheme of things, a very, very safe procedure. Why is it that you are concerned with the sight risk of post laser angle closure (this has never happened in my over two decades of practice) and flashes of light
If you would like to discuss these, and any other, post operative risks I would be happy to assist you.
So what is the take home message? Airplane travel will, in and of itself, not increase your risk of an angle closure attack.
Does this make sense to you?
It was a pleasure to assist you with your question. Please let me know if I can do anything else to help you in the future. Positive Feedback and/or Bonus is welcomed and appreciated.