How High Do Commercial Planes Fly?
Sources: ICAO, FAA, manufacturer specifications · Updated May 2026
Commercial jets typically cruise between FL310 and FL410 — that is 31,000 to 41,000 feet (9.5 to 12.5 km) above sea level. The exact level is chosen for each flight to balance fuel economy, weight, weather, traffic, and winds aloft. The lower stratosphere is preferred because the air is thin (less drag), most weather sits below, and the jet stream can be exploited. Service ceilings differ by type: Boeing 737 / Airbus A320 family typically max out near FL410, the Boeing 777 around FL430, the Boeing 787 and Airbus A350 near FL430, and the Airbus A380 around FL430. Smaller regional jets (CRJ, Embraer E-Jets) usually cruise at FL310–FL370.
Flight levels — the standard altitudes
Above the transition altitude (varies by region, typically 18,000 ft in the US, 3,000–5,000 ft in much of Europe), aircraft use flight levels measured against a standard atmospheric pressure of 1013.25 hPa. FL310 means a pressure altitude of 31,000 ft. The standard rules:
- →Eastbound traffic uses odd flight levels (FL310, FL330, FL350, FL370, FL390, FL410)
- →Westbound traffic uses even flight levels (FL300, FL320, FL340, FL360, FL380, FL400)
- →Under RVSM (Reduced Vertical Separation Minima), the separation between aircraft is 1,000 ft from FL290 to FL410. Above FL410, separation reverts to 2,000 ft
Why so high — five reasons
At 35,000 ft the air is about one-quarter the density of sea level. Drag scales with density, so jet engines burn far less fuel for the same airspeed. The trade-off: engines also produce less thrust in thin air, which is why cruise altitude depends on weight.
The troposphere (where most weather lives) ends at the tropopause — about 36,000 ft at mid-latitudes, lower at the poles, higher in the tropics (up to 55,000 ft). Most thunderstorm tops are below the cruise band, though severe convection can punch through.
Strong west-to-east winds in the upper troposphere can give eastbound flights a 80–140 mph tailwind. Flight planners choose altitudes that ride the jet stream eastbound and skirt around it westbound. See jet stream guide.
High-bypass turbofans operate most efficiently at cold, low-density inlet conditions. Specific fuel consumption drops as altitude increases — until reduced thrust starts to outweigh efficiency gains. That sweet spot lies in the FL330–FL390 band for most narrow-body and wide-body jets.
The cruise band is heavily organized into route structures and altitude assignments. ATC may assign a lower-than-optimal level due to traffic — pilots accept it and accept a small fuel penalty.
Service ceilings by aircraft
Service ceiling is the maximum altitude at which the aircraft can still climb at a specified rate (typically 100 ft/min). It depends on weight; at maximum takeoff weight, ceilings are lower.
Step climbs and weight
A long-haul flight rarely cruises at a single altitude. As fuel burns off, the aircraft becomes lighter and can climb to a higher, more efficient level. Step climbs — typically 2,000 ft at a time — are coordinated with ATC every few hours. A 12-hour flight may climb from FL330 at top of climb to FL370 mid-flight to FL390 in the last third.
What about FL410-plus?
Few civil airliners operate routinely above FL410 because the certified envelope narrows (the spread between high-speed buffet and low-speed stall, sometimes called the "coffin corner"), and RVSM does not extend above that level. Business jets and a few wide-bodies on light loads do operate at FL430–FL450, but airline operations cap most flights at FL410.
Sources
- ICAO Annex 2 — Rules of the Air (flight levels and altimetry)
- FAA Aeronautical Information Manual (AIM) Chapter 4 — Air Traffic Control
- ICAO Doc 7030 — Regional Supplementary Procedures (RVSM)
- Manufacturer Type Certificate Data Sheets (Boeing, Airbus, Embraer, Bombardier)