Rev. Rul. 2026-18, October 9, 2026

Under Section 61 of the Internal Revenue Code (I.R.C. § 61), gross income includes all income from whatever source derived, specifically encompassing fringe benefits provided to employees or independent contractors. When an employer provides noncommercial flights on employer-provided aircraft for personal purposes, the value of the flight must be included in the recipient’s gross income unless a statutory exclusion applies. To reduce administrative friction and valuation disputes regarding fair market value, the Internal Revenue Service provides a safe-harbor valuation methodology under Treasury Regulation Section 1.61-21(g).

Revenue Ruling 2026-18 sets forth the updated Standard Industry Fare Level (SIFL) cents-per-mile rates and terminal charges required to value noncommercial flights taken on employer-provided aircraft during the second half of calendar year 2026 (July 1, 2026, through December 31, 2026). This article examines the factual backdrop of the ruling, the administrative rationale for its publication, the underlying statutory and regulatory rules, the mathematical application of the SIFL formula, and key compliance considerations for tax professionals representing corporate clients and executive taxpayers.

Factual Background and Rationale for Administrative Issuance

The Internal Revenue Code and Treasury Regulations mandate that fringe benefits be valued and recognized in gross income at the time conferred. However, determining the fair market value of personal flights on corporate aircraft poses unique valuation challenges, as charter rates vary widely depending on aircraft type, market conditions, and geographic routing.

To establish uniform administrative standards, “section 1.61-21(g) of the Income Tax Regulations provides a rule for valuing noncommercial flights on employer-provided aircraft.” Specifically, “Section 1.61-21(g)(5) provides an aircraft valuation formula to determine the value of such flights.” Because the underlying economic metrics depend on prevailing commercial aviation costs, “[t]he SIFL cents-per-mile rates in the formula and the terminal charge are calculated by the Department of Transportation (DOT) and are reviewed semi-annually.”

The IRS issues these Revenue Rulings on a semi-annual basis to publish the DOT’s updated figures. The primary objective of Revenue Ruling 2026-18 is to supply CPAs, Enrolled Agents, and payroll administrators with the precise, legally binding valuation figures needed to calculate taxable income, compute federal income tax withholding (FITW), and satisfy FICA/FUTA obligations for noncommercial flights taken between July 1, 2026, and December 31, 2026.

Statutory and Regulatory Analysis

The statutory baseline begins with I.R.C. § 61(a)(1), which establishes that gross income includes fringe benefits. Treasury Regulation Section 1.61-21(a)(1) affirms that an employee must include in gross income the fair market value of any employer-provided fringe benefit, less any amount paid by or on behalf of the employee.

While Treasury Regulation Section 1.61-21(b) sets forth general fair market value principles (often determined by reference to comparable charter rates), Treasury Regulation Section 1.61-21(g) provides an elective, non-discretionary safe-harbor valuation method commonly referred to as the SIFL formula. If an employer elects to utilize the SIFL valuation rule for an aircraft flight, the value generated under the regulation is deemed to equal the fair market value for income tax, payroll tax, and reporting purposes.

As articulated in Revenue Ruling 2026-18, “[t]he value of a flight is determined under the base aircraft valuation formula (also known as the Standard Industry Fare Level formula or SIFL) by multiplying the SIFL cents-per-mile rates applicable for the period during which the flight was taken by the appropriate aircraft multiple provided in section 1.61-21(g)(7) and then adding the applicable terminal charge.”

The mathematical structure of the SIFL formula is expressed as follows:

SIFL Flight Value = (Applicable SIFL Mileage Rate × Flight Distance in Miles × Aircraft Multiple) + Applicable Terminal Charge

The regulatory mechanics require three distinct determinations:

Distance Traveled: The total noncommercial mileage of the flight stage, divided into incremental statutory distance brackets (0–500 miles, 501–1,500 miles, and over 1,500 miles).
Aircraft Multiple: A statutory percentage multiplier derived from Treasury Regulation Section 1.61-21(g)(7), which depends on whether the passenger is a “control employee” or “non-control employee” and the maximum certified takeoff weight of the employer’s aircraft.
Terminal Charge and Mileage Rates: The semi-annually adjusted base rates determined by the Department of Transportation and published by the IRS.

Application of the Law to Second-Half 2026 Flights

Revenue Ruling 2026-18 provides the mandatory rates for flights taken during the period beginning July 1, 2026, and ending December 31, 2026.

The IRS sets forth the following terminal charge and tiered SIFL mileage rates for this specific six-month period:

Applicable Period: July 1, 2026, through December 31, 2026
Terminal Charge: $58.95
SIFL Mileage Rates:
- Mileage Bracket Up to 500 Miles: $0.3225 per mile
- Mileage Bracket 501 to 1,500 Miles: $0.2459 per mile
- Mileage Bracket Over 1,500 Miles: $0.2364 per mile

When applying these rates to client factual scenarios, practitioners must calculate the value for each passenger on a flight-by-flight, leg-by-leg basis. For instance, for a 1,800-mile flight taken by a control employee on a heavy corporate jet (where an aircraft multiple of 300% or 400% applies under Treas. Reg. § 1.61-21(g)(7)), the base SIFL calculation involves applying $0.3225 to the first 500 miles, $0.2459 to miles 501 through 1,500, and $0.2364 to the remaining 300 miles, multiplying the weighted sum by the appropriate aircraft multiple, and finally adding the $58.95 terminal charge.

IRS Conclusions and Practical Considerations for Tax Practitioners

Revenue Ruling 2026-18 establishes definitive tax conclusions for noncommercial employer-provided aircraft usage during the second half of 2026:

Mandatory Application Window: The published terminal charge of $58.95 and the tiered mileage rates ($0.3225, $0.2459, and $0.2364) apply strictly to flights taken between July 1, 2026, and December 31, 2026. Flights taken during the first half of 2026 remain governed by the prior semi-annual revenue ruling.
Interplay with Statutory Disallowance Rules: Tax practitioners should remind clients that valuing a flight under the SIFL rules for income inclusion under I.R.C. § 61 does not override deduction disallowance provisions under I.R.C. § 274(e)(2) or § 274(o) regarding corporate deductions for entertainment aircraft usage by specified individuals.
Payroll and Withholding Deadlines: Employers making SIFL adjustments must ensure proper imputation on Form W-2 (Box 1, 3, 5, and 14 if applicable) and coordinate employment tax deposit requirements under IRS special accounting rules for noncash fringe benefits (e.g., Announcement 85-113).

Drafting information in the ruling reflects that the principal author of Revenue Ruling 2026-18 is Kathleen Edmondson of the Office of Associate Chief Counsel (Employee Benefits, Exempt Organizations and Employment Taxes).

Prepared with assistance from Gemini Notebook.