Sometimes when i try sleep on a plane i feel breathless but if am sat with my eyes open am fine? why can this happen just when i try sleep on a flight

Postural obstruction: The position of your neck when trying to sleep sitting upright is compromising the airway. If you are overweight losing weight would help. You may try a neck pillow to support your head so that your neck is not bent in a way that interferes with the airway. Wish you good health! - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex, if you have sex.