crvena55, your condition would probably be a minor case of hypothyroidism brought about by removal of the most active part of your thyroid gland. Well this condition is generally less problematic than hyperthyroidism. As long as it is manageable by medication, you should have no problem as a cabin crew member. The only thing about long haul flying is that you tend to forget to take your medication on time due to time zone differences and fatigue! So you need to work out a reliable medication management routine. All the best.