Flight Friday: CFM Leap Leads Narrowbody Fleet Utilization Surge

As September marks the first month following the Northern Hemisphere’s peak summer season, this week’s Flight Friday examines narrowbody aircraft and their engines, comparing “flown” days across recent Septembers.

For clarity, a flown day is a 24-hour UTC period where an aircraft had an arrival. The inverse of that is a “ground” day, where an aircraft didn’t have an arrival.

A ground day could be for many reasons: maintenance, scheduling, aircraft on ground (AOG), or many of the other reasons that mean an aircraft doesn’t fly.

With fuel prices remaining high, increased inflation, and the possible impact of these factors on travel demand, operators are making conscious decisions when it comes to utilizing their fleets.

Naturally, as the peak summer demand fades, operators start their maintenance visits, so there is always a softening of utilization, but the data shows that not all engines are created equal. 

The CFM International Leap is operating at 90%-plus flown days in September 2026. This is a culmination of steady and consistent growth from 2023. The Leap-powered aircraft have yet to really hit their heavy maintenance checks window, so the impact of maintenance on ground days is relatively limited.

Operators with mixed-engine fleets are increasingly selecting the latest-generation technology to complete flights, driven by superior fuel efficiency.

The CFM56 and the IAE V2500-powered aircraft are in their heavy maintenance windows, and we can see a lowering of flown days in September 2026 to a touch below 80%.

So, we are probably seeing the impact of maintenance and the addition of the impact of high fuel prices beginning to slightly throttle back utilization, as operators and the traveling public remain cost-conscious.

The Pratt & Whitney PW1000G (GTF) has seen a marked improvement in flown days. With an almost 10% increase from September 2024, Pratt and its risk-sharing partner MTU Aero Engines have worked hard to turn engines around to resolve the durability issues that happen with the introduction of new engines.