Fuel at Six-Month Highs and the Quiet Ways Pilots Are Changing How They Fly

100LL and Jet A both hit six-month highs in September, and an AVweb poll asking pilots whether fuel prices are changing how they fly came back with a clear answer: yes, in measurable ways. The adaptations range from genuinely smart fuel planning strategies to at least one behavioral shift with a direct safety dimension worth understanding.

What Drove the September Fuel Price Spike

The national average for 100LL has been trending upward since late summer, tracking closely with crude oil movements and the seasonal refinery transition that occurs each fall when facilities reconfigure for winter fuel blends. Jet A followed the same pattern - a sustained climb that began in August and did not level off when most observers expected it to.

The retail price at the pump typically lags wholesale movements by two to four weeks. What pilots saw on fuel displays in September largely reflected supply chain conditions from August. By the time it reaches the pump, the market has usually already moved again.

Price variation across the country is significant. Pilots at busy Class C airports with multiple FBOs competing for business may see 100LL hovering in the six-to-seven dollar range. Pilots at single-pump uncontrolled fields are often paying more. In Alaska and remote mountain regions, fuel transported by truck over long distances can reach prices in a different category entirely.

Why Avgas Pricing Doesn’t Behave Like Other Fuels

100LL is not a mainstream fuel. It is produced at a handful of refineries, distributed through a specialized network, and critically, it contains tetraethyl lead - the additive that provides the octane rating high-compression piston aircraft engines require. There is essentially one major producer of tetraethyl lead still operating in the global market, and worldwide demand is shrinking as other industries phase it out.

That shrinking demand creates pricing dynamics that don’t respond the way typical commodity markets do. When supply tightens for any reason, wholesale avgas prices move quickly - and they move up faster than they come back down. The September spike had identifiable causes: crude oil pushed higher through late summer, refinery margins were already tight, and summer flying season demand had drawn down inventories more than forecasters expected.

How Pilots Are Responding: The Four Adaptations

1. Fuel planning and tankering. The most common adaptation is spending more time before a flight comparing fuel prices across a route rather than defaulting to the home airport. Tools like FuelForward, 100LL.com, and the fuel price features built into ForeFlight and Garmin Pilot make this a standard pre-flight step for cross-country pilots.

This is fuel tankering - a practice airlines have used for decades. If fuel at the departure airport is significantly cheaper than at the destination, and the aircraft can legally and safely carry the extra load, topping off early and skipping the expensive stop can produce real savings. The math requires care: extra fuel adds weight, and weight burns fuel. But for most light aircraft over typical GA legs, the crossover point where additional weight erodes savings doesn’t arrive until the price differential is fairly small. On a cross-country with a dollar-or-more price gap and adequate useful load margin, the savings can be meaningful across a season.

2. Route adjustments. Some pilots are routing not just for wind and weather, but for fuel price. An airport fifteen miles off the direct track with competitive pricing can still come out ahead mathematically if the differential is large enough. Others are actively avoiding airports known for full-service-only pricing where self-serve isn’t available.

3. Mogas. A significant portion of the certificated light aircraft fleet can legally operate on unleaded automotive fuel under Supplemental Type Certificates (STCs) issued by the FAA. For pilots with an appropriate STC and access to ethanol-free automotive fuel, the price difference can reach $1.50 to $2.00 per gallon or more compared to 100LL, depending on regional pricing.

For a Cessna 172 burning 8 gallons per hour, a two-dollar-per-gallon difference is $16 saved every flight hour. Over 50 hours in a season, that’s $800. Over 100 hours, $1,600. The catch is availability and discipline: not every airport sells mogas, ethanol content in automotive fuel varies by season and region, and ethanol is incompatible with most aircraft fuel systems. Sourcing and storage require additional preflight rigor. For pilots who’ve done the homework and hold the right STC, it’s a legitimate option that gets more attention every time avgas ticks upward.

4. Reducing fuel loads - and why this one matters.

Some pilots responding to the AVweb poll indicated they are carrying less fuel. This is the adaptation that deserves direct attention.

The Safety Case for Carrying More Fuel, Not Less

FAR Part 91 sets legal minimums: day VFR requires enough fuel to reach the destination plus 30 minutes at normal cruise; night VFR, 45 minutes; IFR, destination plus alternate plus 45 minutes. Those numbers represent the floor for handling a reasonable deviation from the planned flight - not a budget target optimized against the current price of avgas.

Consider a straightforward scenario: clear skies, light winds, a familiar route. A pilot tops off to just above legal minimum because avgas just crossed $7 per gallon. Then an unexpected 15-knot headwind component develops in the final hour. Or a runway closure at the destination adds 20 minutes to the approach. Or pop-up convective activity forces a 20-mile deviation. Any one of those events is manageable with a comfortable fuel reserve. Combined, starting from minimum legal fuel, they place a pilot doing fuel calculations in the cockpit under pressure rather than making aeronautical decisions from a position of margin.

The math on flying minimum fuel to save money is the wrong math. A buffer that costs an extra ten or fifteen dollars at the pump is the cheapest line item in an aircraft’s operating budget. Carry what you need to handle the unexpected.

What This Means for Flight Training and Flying Clubs

The fuel price environment has compounding effects on the broader GA community. When 100LL increases by $1 per gallon, a student flying a Cessna 172 at 8 gallons per hour pays $8 more per flight hour in fuel alone. A private pilot certificate typically requires 40 to 60 hours of flight time, meaning a single dollar-per-gallon increase adds $300 to $500 to the total cost of certification. Over the price movements of the past several years, the cumulative impact on training costs is substantial.

Some students are responding by spacing lessons further apart to manage costs. This creates its own problem: skills regress between flights. A student flying weekly makes faster progress than one flying every three weeks. Slower progress means more total hours to complete the curriculum, which means higher total cost. Price pressure accelerates the cycle - which is one reason flight training pipelines have been under stress even as professional pilot demand has never been higher.

Flying clubs face a parallel tension. When fuel spikes, clubs must choose between raising hourly rates and risking lower utilization, or holding rates and watching operating reserves drain. Most do some version of both. The result is typically that members fly a little less - which means less currency and, consequently, less safe flying.

The Longer-Term Picture: Unleaded Avgas

The structural reason 100LL prices behave the way they do comes back to the lead. As other industries phase out leaded fuel globally, the economics of producing tetraethyl lead become more challenging. At some point, the supply picture for avgas as currently formulated becomes difficult regardless of what crude oil does.

The transition to unleaded avgas is actively underway. The FAA’s EAGLE initiative (Eliminate Aviation Gasoline Lead Emissions) has been working toward a coordinated fleet transition. GAMI’s G100UL, an unleaded avgas formulation, has received authorization for use across essentially all piston aircraft engines currently approved for 100LL - a significant certification milestone. Swift Fuels has its own unleaded product with a different chemistry and certification history.

Whether one product dominates or multiple unleaded options coexist is still being determined by market forces and the regulatory process. For pilots already operating aircraft STC’d for mogas or for one of the new unleaded formulations, part of that future is accessible today. For everyone else, the timeline depends on when these products reach individual airports - which depends on FBO investment decisions, regional demand, and distribution economics.

The transition is coming. Whether it arrives on a timeline that provides price relief or simply as a compliance event will likely differ by region.

Practical Steps for Right Now

• Check fuel prices along every route you fly regularly. FuelForward, 100LL.com, ForeFlight, and Garmin Pilot all provide current price data by airport. This is a five-minute pre-flight step.
• If your aircraft has a mogas STC, understand local availability and do the sourcing homework on ethanol content before using it.
• If you fly with a club, ask whether the club has explored volume purchasing arrangements with local FBOs. Some clubs have negotiated meaningful discounts based on consistent volume.
• Plan your fuel load from the logic of what you need to handle the unexpected - not from the minimum the regulations allow.

Key Takeaways

• 100LL and Jet A hit six-month highs in September, driven by crude oil movements, tight refinery margins, and lower-than-expected summer inventory levels.
• Retail avgas prices lag wholesale movements by two to four weeks, meaning the price at the pump today reflects supply chain conditions from last month.
• Smart adaptations include fuel tankering, route adjustments for price, and mogas use where an appropriate STC applies - the savings over a full season can reach hundreds to over a thousand dollars.
• Reducing fuel loads to save money is the wrong trade. FAR Part 91 minimums are floors for safety, not fuel budgets.
• The FAA’s EAGLE initiative and GAMI’s G100UL authorization represent real progress toward unleaded avgas, but distribution timeline and price impact will vary significantly by region.