hi guys.....
thanks for the back up. the flight is manchester to singapore then sydney with singapore airlines. my dad does have a mild form of copd which requires just normal medication here, but i was worried about the oxygen levels in the plane at altitude. as far as i am aware the insurance company have given him the all clear to fly, but then again i am not sure what he has told them, and whether he has given them the full picture.
at least the flight is not until october, so at least we have time to make sure everything is all right with his planned trip.
Forgot to say, big thanks to gadgetman for a thorough explanation.