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The story begins with the narrator waking up on an airplane due to a "bump," which she assumes to be from turbulence. Everything seems normal at first, and her thoughts drift. I think most of the text is her own internal monologue and reminisces, but she keeps noticing minor details that strike her as strange. She slowly comes to suspect that the plane was destroyed (by a bomb?) and everyone aboard is being taken into the Egyptian afterlife.
The flight may have been on its way to Cairo or may have just been flying over the area, but I don't recall any particular reason why it should have been the Egyptian afterlife other than that. She may have spotted some pyramids through the window and been thinking about the funeral preparations for the afterlife journey of the ancient Egyptian kings somewhere early in the story.
Towards the end, she looks out the window and spots crocodile-like monsters in the river (the Nile) below. It ends on a note of continuing ever onward into the unknown as things slowly become stranger. I was pretty sure that this was a Dan Simmons story, but I don't see any promising short fiction titles in his bibliography.
I was reminded of this story by another question, but this is apparently not the same one. The story about which I'm thinking definitely begins with the narrator waking up on the plane, and the plane's cabin (plus what can be seen out its windows) is the setting for the entire story.