How High Do Airliners Cruise? Average Cruise Level, Certified Ceilings, Flight-Level Use and Cabin Pressure Altitude from EUROCONTROL, EASA, US Regulatory and OpenSky Network Data, 1995–2026

Cruise altitude governs fuel burn, airspace capacity and the pressure environment of passengers, yet no US body publishes an average achieved cruise altitude. We combine published statistics with limits and a direct measurement. EUROCONTROL data show that instrument flights above FL200 over Europe reached an average maximum level of FL350 (35,000 ft) in July 2024, about 500 ft above 2018, while the most-requested level in flight plans rose from FL330 in 1995 to FL380 in 2021 and the share of flights requesting levels above FL350 from 6% to 40%. European type-certificate data sheets place certified ceilings between 39,100 ft (Airbus A320 and A321) and 45,100 ft (Boeing 747-400), with large business jets at 51,000 ft. US rules assign odd levels to eastbound and even levels to westbound traffic, 1,000 ft apart in reduced vertical separation minimum (RVSM) airspace. From an OpenSky Network snapshot of 12,472 tracked aircraft at 19:32 UTC on 27 September 2026 we identified 4,810 in level cruise at or above 20,000 ft; they averaged 35,371 ft (median 36,000 ft), and 53.5% were between 35,000 and 39,999 ft. Over US states, 99.2% of eastbound aircraft between FL290 and FL410 were on odd levels. Sixteen repeated snapshots gave US means between 34,591 and 34,948 ft. Inside the aircraft, a published study of 207 US domestic flights found a mean peak cabin altitude of 6,341 ft against the 8,000 ft design limit, rising to 7,085 ft on flights over 750 miles.