One Hundred LL at a Six-Month High: The October Fuel Spike, What It Costs Per Hobbs Hour, and What Comes Next

100LL and Jet A are both at six-month highs as of October 2026, following four consecutive months of price increases for both grades. The climb has been steady since late June, driven by crude oil markets, a concentrated refinery base, and seasonal demand pressure. For general aviation pilots, that means every Hobbs entry costs more - and the underlying conditions aren’t resolving quickly.

What the Numbers Actually Mean Per Flight Hour

The impact is straightforward to calculate and hard to ignore. A Cessna 172 burning approximately 8 gallons per hour means a 50-hour flying season consumes roughly 400 gallons. At a dollar or more per gallon increase over six months, that’s a meaningful hit to an annual flying budget before accounting for anything else. For flight schools running a fleet, the numbers scale fast.

This increase isn’t a sharp spike that corrects in a week. It’s a sustained grind, which is in some ways harder to plan around than a sudden jump.

Why 100LL Prices Don’t Behave Like Gas Station Prices

Crude oil is the starting point for any aviation fuel price discussion, but 100LL doesn’t track crude the way automobile gasoline does. It has its own supply chain, its own refining process, and a far smaller market. Only a handful of refineries in the United States produce 100LL. That concentration means supply disruptions, scheduled maintenance cycles, and seasonal demand swings hit the price harder and faster than they would in a commodity with broader production.

The lead additive itself - tetraethyl lead - is sourced from a limited number of suppliers globally. Any disruption on that side amplifies immediately through the finished product price.

Why Jet A Is Also Up

Jet A tracks crude more closely than 100LL because it’s produced in much higher volumes and shares refining infrastructure with commercial aviation fuel. The complication is that fall is a period of elevated jet fuel consumption as airline traffic holds into the holiday season, and airline load factors are currently strong. That competition for refining capacity doesn’t disappear when you’re at an FBO filling a turboprop or light piston twin. Jet A pilots feel the same seasonal pressure the airlines feel.

Practical Steps for Cross-Country Fuel Planning Right Now

Check prices before you file. The spread between airports is real and worth knowing in advance. Flight planning apps including ForeFlight and FlyQ, and dedicated fuel price aggregators like AirNav, display current FBO prices before departure. A $1.50 spread per gallon on a 25-gallon fill is $37.50. Over a full season, that adds up.

Self-serve pumps are almost always cheaper than full-service fuel. Without the labor cost and FBO overhead, the savings get passed to the pilot. If your aircraft is straightforward to fuel and the self-serve option is on the field, the math generally favors it.

If you fly with a club or flight school, verify whether your wet rate reflects current fuel costs. Some clubs absorb short-term swings and adjust quarterly. Others pass increases through immediately. Know your situation before planning a long trip.

One Thing That Should Not Change: Your Fuel Reserves

When fuel costs rise, there’s sometimes pressure - conscious or not - to trim reserves. Don’t. The legal minimum is not the operational minimum. The 30 minutes of extra fuel you carried before the price increase is worth carrying now. The only time the cost of that fuel matters is if you land with it. If you don’t land with it, you needed it.

Fuel exhaustion and fuel starvation continue to appear in NTSB accident reports with uncomfortable regularity. Rising prices are not a reason to change reserve habits.

The Unleaded Transition: Medium-Term Variable That Could Change Everything

This price increase is happening against the backdrop of the most significant fuel transition in general aviation history. The EAGLE initiative (Eliminate Aviation Gasoline Lead Emissions) set a goal of deploying a 100LL replacement by the end of 2023. That deadline passed, and the transition remains ongoing.

General Aviation Modifications Incorporated (GAMI) received FAA supplemental type certificate approval for their G100UL formula - an unleaded drop-in replacement for most piston aircraft. Swift Fuels has UL94 approved for lower-compression engines. The FAA issued a fleet authorization order in 2023 opening the door for most piston aircraft to use the GAMI formula without individual STC paperwork.

The bottleneck is infrastructure. Airports need certification for the new formulations, fuel trucks need dedicated labeling, and refineries need to commit capital investment to produce the new fuels at scale. Right now, 100LL remains the dominant fuel at the overwhelming majority of U.S. airports, and as long as that’s true, its price is what pilots pay.

There’s a structural argument worth understanding: one of the long-term cases for accelerating the unleaded transition is price stabilization. Lead additives carry specific supply dependencies, and a fuel supply chain tied to a small, specialized market will always be more volatile than one integrated into a broader energy ecosystem. A wider production base means more competition, which tends to moderate price swings over time. That’s a future-tense argument for now - but it’s a real one.

What This Means for the Pilot Pipeline

Aviation isn’t unique in facing input cost pressure, but GA is a discretionary activity for most of the people in it. The economics of flying are already tight enough that sustained cost increases reshape who can afford to fly regularly. AOPA and the Experimental Aircraft Association (EAA) track trends in flight school closures, club consolidation, and reduced student starts closely.

The connection runs downstream: fewer people building hours in the near term means fewer reaching the regional airlines, which are already stretched. AOPA and EAA have both advocated for policies addressing GA flying costs, including fuel tax relief and acceleration of the unleaded transition to broaden the supply base.

For student pilots and hour-builders, the best protection for a training budget right now is maximizing what you get from each flight. Thorough preflight briefing, clear maneuver plans before departure, knowing what you’re going to practice before the wheels leave the ground. Every Hobbs minute spent figuring out what to do next is a minute that could have built actual skill.

Key Takeaways

• 100LL and Jet A are both at six-month highs as of October 2026, up for four consecutive months since late June.
• The increase is structural, not a sharp spike: a concentrated refinery base, tetraethyl lead supply dependencies, and seasonal demand are all contributing.
• Use ForeFlight, FlyQ, or AirNav to compare fuel prices before every cross-country; the spread between airports can be significant.
• Do not trim fuel reserves in response to higher fuel costs - the legal minimum is not the operational minimum.
• The GAMI G100UL unleaded approval and the broader EAGLE initiative represent the medium-term variable most likely to change the structure of this market; infrastructure deployment remains the bottleneck.