Airlines

Heights

• Orbital height (for a stable orbit): 150km or ~500,000 ft
• Typical commerical airline flying altitude: 30,000 to 40,000 ft

FAQ

How high can an airline fly?

• Each aircraft has a maximum altitude (service ceiling) at which is it rated to fly. Typically it’s 42,000 feet.
• At higher altitudes, the air is thinner which produces less resistance allowing them to fly faster with less fuel.
• There are some tradeoffs. At higher altitudes, you have jet stream winds which you have to adjust height to control.
• If you fly too high, the air may get too thin and cause engines to not produce enough thrust and wings can’t produce enough lift.
• If the cabin de-pressurizes at a high altitude, the plane needs to descend down to a lower altitude. The TUC is the time of useful consciousness i.e how long a passenger is expected to stay conscious to put their oxygen mask on. At 35,000 feet this is 15-30 seconds. At 60,000 feet, this is 5 seconds.