Hi Dear !! Thanks for your query to HCM . Read and reviewed your query and health concerns. IN the given situation of Yours, seem to suffer from-Flight Phobia,for your age old Dad. Dear,as he is on low steroids and maintained lately at those levels,temporal arteritis is not a big problem. Following are the risks and Do s- Risk of Increased temporal pains,due to volatile Blood pressure changes. Ask your father to take higher doses of steroids,till he checks with your doctor to tide over the increased headache, which could disturb him. The real risk is from -his advanced age and the inbuilt volatility of his blood pressure and chances of chest pain.For this ,get the cardiac condition OKeyed from his doctor there with you Dad and get cardiac doses adjusted for this long flight. And alert the flight carrier for any involved risk on flight. This plan would reduce your dilemma from long flight for your Dad. Hope this would help you to plan further of this complex illness of yours. If need be, update any health issue 24 x 7 by a direct question to ME, at following HCM link- Dear, if satisfied,Don t forget to close this query with YOUR pleasing feedback comments to rate this reply and service, to boost the morale of incoming Emergency patients like YOU, at HCM services. If you want to update more details and ask more update queries , You are most Welcome herewith !! Good Day!! Wishing Good Healthy Life in time to come!! Dr.Savaskar M.N. Senior Surgical Specialist M.S.Genl-CVTS