# Aviation propulsion: Correlation Prices it moves with, and why Source page: https://www.materialinsights.org/energy/e_aviation/correlation/ The index covers aircraft engines and parts, made by very few firms on long contracts. Prices follow nickel superalloys, titanium, precision machining and certification, plus airline order books and spare parts demand, so they rise steadily and rarely respond to fuel. Price index **US PPI: aircraft engines and engine parts** index · monthly, Jan 2006 to Sep 2026 #### What its price moves with Selected link ##### Aviation propulsion and Nickel Monthly changes 0.15 little or none correlation 12-month changes -0.02 little or none correlation Last 5 years 0.18 monthly changes Lead or lag none No clear lead or lag Price function, Jan 2006 to Sep 2026 Aviation propulsion ≈ 609.7 × (Nickel)^-0.10 R² 0.07 On this fit, a 10% higher nickel price goes with a −1.0% lower aviation propulsion price over the long run. Units: index and $/mt. The fit is loose, so treat the function as a rough guide. Chart: Aviation propulsion and Nickel prices rebased to 100 at Jan 2006, log scale Both prices rebased to 100 at Jan 2006, on a log scale so equal percentage moves look the same size. Chart: Aviation propulsion price against Nickel price, monthly, log scales, with fitted line Each dot is one month; paler dots are older (2006), darker dots recent (2026); the ringed dot is the latest month. The dashed line is the fitted price function. Both axes are logarithmic. Commodity [Ni Nickel](https://www.materialinsights.org/commodities/nickel/)Superalloys 0.15 Turbine blades, discs and combustors are made from nickel superalloys. Monthly moves correlate at only 0.15 with nickel, because metal is a small part of an engine's price and makers fix long-term supply deals for alloy. little or none co-movement month to month · 249 months Show charts Commodity [Ti Titanium](https://www.materialinsights.org/commodities/titanium/)Fan and compressor 0.05 Fan blades, compressor parts and engine casings use titanium alloys for strength at low weight. Monthly moves correlate at 0.23 over the last five years, a weak link, since aerospace titanium is bought on multi-year contracts. little or none co-movement month to month · 249 months Show charts Commodity [Re Rhenium](https://www.materialinsights.org/commodities/rhenium/)Blade alloy The hottest single-crystal turbine blades contain small amounts of rhenium, a rare by-product of copper and molybdenum mining. Engine makers are its largest users, so aviation demand drives rhenium prices, which have no series here. Not enough overlapping price history to measure. Chemical [HVO Renewable diesel and SAF](https://www.materialinsights.org/energy/hvo_saf/)Fuel 0.01 Jet engines burn kerosene and, increasingly, sustainable aviation fuel. The diesel proxy used for these fuels correlates at 0.01 monthly with the engine index, showing that fuel costs change airline profits but do not set engine prices. little or none co-movement month to month · 249 months Show charts Energy [CCGT Gas turbines and combined cycle](https://www.materialinsights.org/energy/e_gas_turbines/)Shared technology 0.15 Industrial gas turbines are close cousins of jet engines, often from the same makers and alloys. Monthly moves correlate at 0.15 and yearly at 0.29, a modest link because the two serve different order cycles in power and airlines. little or none co-movement month to month · 234 months Show charts Energy [Oil Crude oil](https://www.materialinsights.org/energy/crude_oil/)Fuel cost driver 0.02 Oil prices drive jet fuel costs, which push airlines to replace older engines with more efficient ones. The engine index barely follows, with monthly moves correlating at 0.02, because orders are placed years ahead and prices are set by contract. little or none co-movement month to month · 249 months Show charts How to read these numbers **Correlation of monthly changes** (the number in the coloured pill) compares how much each price moved, month by month, since 2006 or the first month both series exist. It runs from −1 to +1: near +1 the two usually rise and fall in the same months, near 0 there is no link, and a negative number means they tend to move in opposite directions. Above 0.7 is strong, 0.4 to 0.7 moderate, 0.2 to 0.4 weak. **12-month changes** compare year-on-year moves, which shows whether two prices share the same cycles even when the month-to-month noise differs. **Price function** is a straight-line fit of the two prices on logarithmic scales: price ≈ k × (partner price)^β. β is how much this price moves, in per cent, for a 1% move in the partner over the whole period, and R² is the share of the variation the fit explains. Two prices that both drift up with inflation can fit well without any real link, so read it together with the monthly correlation. **Lead or lag** checks whether the monthly correlation is clearly higher when one price is shifted by 1 to 6 months. Correlation is not cause. The reasons on each card explain the economic link; the numbers show how strongly it has shown up in prices. Proxy series are US producer price indexes or related prices and can blur the real link. Data: World Bank Commodity Price Data (Pink Sheet), October 2026; US Bureau of Labor Statistics producer price indexes, IMF primary commodity prices and US EIA prices via FRED, Federal Reserve Bank of St. Louis, retrieved November 2026. Calculations by this site. ## Other sections - [Summary](https://www.materialinsights.org/energy/e_aviation/index.md) - [Overview](https://www.materialinsights.org/energy/e_aviation/overview/index.md) - [Science and limits](https://www.materialinsights.org/energy/e_aviation/science/index.md) - [Value chain](https://www.materialinsights.org/energy/e_aviation/valuechain/index.md) - [Unit economics](https://www.materialinsights.org/energy/e_aviation/economics/index.md) - [Engineering methods](https://www.materialinsights.org/energy/e_aviation/methods/index.md) - [Equipment and suppliers](https://www.materialinsights.org/energy/e_aviation/equipment/index.md) - [Relationships](https://www.materialinsights.org/energy/e_aviation/links/index.md)