If you have controlled high blood pressure, you can fly on a plane. If your blood pressure is very high and uncontrolled, check with your doctor before flying. If you also have another condition such as heart or kidney failure, check with your doctor before travelling.
Whenever you travel, remember to carry your medicine in your carry-on bag. Keep an extra supply in your checked luggage in case your carry-on is lost or stolen.
You’re good to go, as long as your blood pressure is under control!