Let me see if I understand. (A bird flew understand a cloud.) It is wrong to say "I am relieved that this flight is finally over." because "A bird flew over a cloud" makes sense? (A bird flew sense a cloud.)
I know, I know! "I am relieved that this flight is finally over" sounds perfect, doesn't it? All I can say is that mother would have preferred,
"I am relieved that this flight has finally come to an end."
Regards,
PS: Remember that famous line from the opening of Star Trek? To boldly go where no man has gone before.
Wrong. Split infinitives are naughty. Nevertheless, "to go boldly where no man has gone before" sounds just plain silly, even though it is correct.