Even if you have chronic obstructive pulmonary disease (COPD), emphysema, chronic bronchitis, cystic fibrosis, asthma, or heart disease and need an oxygen supply, you should be able to travel so long as you consult closely with your physician and then follow the advice received.
For COPD patients, whose main problem is moving air in and out of their lungs, getting sufficient oxygen is vital. Therefore, it is important that nothing be undertaken which inhibits this function. When traveling by car, train, or bus, COPD patients and others needing supplementary oxygen should have a supply available in case they pass through areas of excess air pollution. They should also avoid travel in a confined area, such as a bus where smoking is permitted, and ensure that they keep out of extreme temperatures, both hot and cold.

Oxygen deprivation is the biggest problem for people with pulmonary and heart conditions. If persons with these conditions intend to travel to places at high altitudes where both oxygen and air pressure are greatly reduced, it is very important that they check with their doctor, who will probably administer breathing tests to monitor their lung power. They should strictly follow the advice given.
Air travel is a special form of altitude problem since almost all aircraft fly above 21,000 feet. Aircraft cabins are normally pressurized at between 5,000 and 6,000 feet (i.e., the altitude of the mile high city, Denver), so that the oxygen level of the air is considerably reduced. However, air travel offers many advantages for heart and lung patients since it is quick and involves little activity.

If you are able to walk a full block reasonably fast you should be able to fly. If in doubt, check with your physician. Most airlines will provide inflight oxygen for which a charge will be made, if they are given 48 hours advance notice. You should obtain a doctor’s letter stating your condition, your suitability for travel and the oxygen supply (litres per minute) you require. If you have your own equipment, this must be empty and carried as checked luggage (free of charge).
With advance notice, airlines will also provide a wheelchair to and from your aircraft and will preboard you and provide seating where you can receive your oxygen supply in a non-smoking area. If you require an inflight oxygen supply, it is a good idea, where possible, to take a direct or nonstop flight to your destination. Changing planes is not only very stressful and physically taxing, but can also be extremely expensive because there will be a charge for oxygen for each individual flight and possibly also at the airport between planes. Check before you fly.

For oxygen supplies at your destination, your normal supplier can probably give you the name of a company who can deliver what you need on arrival. Overseas one can also locate suppliers, sometimes affiliated with U.S. manufacturers, sometimes local.