It is OK to fly with glaucoma as long as if you didn't have any retinal surgery which injected an air bubble to hold retina in place. The bubble might get expanded at heights. If you didn't have such surgery, then it is no problem to travel by flight. Actually glaucoma is a eye condition that intraocular pressure increased to damage the optic nerves. At the beginning, you won't feel anything wrong with your eyes or vision. Because the high pressure in eyes doesn't cause any pain or uncomfortable feelings. Doctor will not give your any special treatment but only requires regular eye examination to monitor the IOP. You can just live your daily life as normally. Don't worry too much. You can also see, watch TV or movies, use computors or do some normal exercises. It does not impact your daily life. Normally glaucoma develops very slow, once the oculist finds out the IOP increase sharply and vision impairment is possible, he/she would give your some proper treatment, such as eye drops which can lower the IOP. With glaucoma, you'd better quit coffee and smoking and intake less saturated fat to maintain the health of blood vessels.
No, you can't take the plane which is not safe because of the high eye pressure when the plane takes off. You'd better wait for one month's basic recovery. Or else, taking plane will affect your recovery at the eyes. You'd better protect the eyes carefully and keep on using the medical care to treat the eyes.
Well, you should not have plane when you have glaucoma. As we know that glaucoma is a condition of the eye that occurs as a result of your eye pressure. And generally speaking, the high pressure caused by glaucoma may damage the optic nerve, a bundle of nerve fiber tissues that sends visual cues to the brain. So we can say that eye pressure can be the big problem of the glaucoma. And when you have a fly, because of the gravity, it will just increase eye pressure. In that way, it will just make your glaucoma become serious. So you should avoid it.