My mother has an abdominal aortic aneurysm (AAA). She lives in the US, but would like to fly here to see me. She asked one doctor about flying and the answer was 'no way', but a second opinion was more positive. What would be your advice?

Dr Jules Eden replies: The aorta is the main arterial blood vessel that runs through the body. If due to weakness in the walls it becomes distorted and balloons to a larger size, it is called an aneurysm. The risk of this is that it can burst or the walls dissect along its length. This then results in a dramatic loss of blood into the abdomen, or the cutting off of blood to tributaries that run to other organs, such as the kidneys. Such an episode would require an immediate four-hour operation to replace the affected vessel, so imagine the problems if this were to happen in flight. Your mother needs to find out exactly what the chances of it bursting are. If her surgeon feels that there is more than a 1-2% chance of this occurring, then she should have the problem surgically corrected before travelling.

My partner and I plan to return home to Australia next year with our, by then, seven-month-old. Is it safe for the child if we make a week-long stopover in South Korea?

The main shots that an adult would have for South Korea are hepatitis A and typhoid, along with, perhaps, Japanese encephalitis. The specification from the vaccine makers is that they will not guarantee safety and efficacy for under one-year-olds. Therefore, you would be advised to take a direct flight (ie without leaving the stop-over airport) to Australia.

· If you have any questions you want to ask Dr Jules Eden, email travel.doctor@theguardian.com, or write to The Flying Doctor, The Guardian, 119 Farringdon Road, London EC1 3ER.