The mechanism: Section 45Z's clean fuel production credit — recently reshaped by Treasury and IRS guidance and narrowed by this year's tax legislation, which cut the maximum SAF credit from $1.75 to $1.00 per gallon and added a 2026 rule requiring North American feedstock — pays fuel producers, not airlines. To capture that subsidy, refiners need a buyer locked in for years. Airlines supply that buyer, signing offtake agreements running a decade or two, often at two-to-three-times the price of conventional jet fuel before the credit is netted in. The politics read as "Washington helps aviation go green." The cash-flow reality is that carriers are underwriting the credit risk and construction risk of unproven producers, prepaying for capacity that may never scale, at prices fixed years before delivery.
Who cashes in: The winners are the producers and the equipment makers selling into the buildout, not the airlines footing the offtake bill. GE Aerospace (GE) benefits regardless of fuel chemistry — SAF-compatible engines and aftermarket servicing revenue accrue whether the fuel is profitable for its buyer or not, and GE carries none of the offtake liability. Honeywell (HON), though outside this core universe, licenses SAF processing technology and is a direct beneficiary of every new production unit permitted under 45Z's certification rules. Within the named universe, Heico (HEI) and TransDigm (TDG) sit furthest from the exposure: both sell proprietary aftermarket parts priced on monopoly-like power over legacy fleets, insulated from fuel-cost volatility and collecting regardless of who wins the SAF subsidy fight.