prior-year period which included the delivery of a 757 P2F conversion aircraft. Excluding whole assets, sales in the fourth quarter of 2024 were up 91.7% year-over-year, driven by higher leasing and USM volume. The Company had nine additional engines and one B757 P2F aircraft on lease during the fourth quarter of 2024 compared to the prior year period.
Technical Operations (“TechOps”) revenue increased 3.1% to $30.7 million in the fourth quarter of 2024 from $29.8 million in the fourth quarter of 2023 primarily due to higher revenues from the Company’s aerostructures unit and contributions from Millington, TN, our new heavy MRO facility, that went online during the year.
Gross margin was 31.4% in the fourth quarter of 2024 compared to 25.9% in the same period last year, due to a sales mix that included higher-margin whole engine and airframe USM.
Selling, general, and administrative expenses were $24.8 million in the fourth quarter of 2024 versus $25.5 million in the fourth quarter of 2023. AerSale incurred $1.2 million of share-based compensation expense in the fourth quarter of 2024, versus $3.1 million in the fourth quarter of 2023.
Income from operations was $4.9 million in the fourth quarter of 2024 compared to a loss from operations of $1.1 million in the fourth quarter of 2023.
Income tax expense was $1.8 million in the fourth quarter of 2024, compared to income tax expense of $2.1 million in the fourth quarter of 2023.
GAAP net income for the fourth quarter of 2024 was $2.7 million, compared to GAAP net loss of $2.7 million in the prior year period. During the fourth quarter of 2024, the Company recognized $1.2 million of share-based compensation expenses within payroll expenses, $1.1 million in non-cash inventory write-down recorded in the cost of products line, $0.4 million in facility relocation costs, $0.2 million in restructuring costs, and a gain of $1.0 million on insurance proceeds. Excluding these non-cash and unusual items adjusted for tax, adjusted net income was $4.8 million in the fourth quarter of 2024, compared to adjusted net loss of $0.1 million in the fourth quarter of 2023.
Diluted earnings per share was $0.05 for the fourth quarter of 2024 and diluted loss per share was $0.08 in the fourth quarter of 2023. Adjusted for the non-cash and unusual items noted above, adjusted diluted earnings per share was $0.09 for the fourth quarter of 2024 while adjusted diluted loss per share of $0.02 in the fourth quarter of 2023.
Adjusted EBITDA in the fourth quarter of 2024 was $13.0 million versus $6.0 million in the fourth quarter of 2023. Higher adjusted EBITDA was primarily due to higher sales volume during the period and lower period expenses.
Full Year 2024 Results of Operations
For the full year 2024, AerSale reported revenue of $345.1 million, which represents an increase of 3.2% from $334.5 million for the full year 2023. Asset Management revenue was $215.5 million, compared to $215.2 million in the full year 2023, as USM volume and increased assets in the lease pool offset lower whole asset sales.
TechOps revenue for the full year of 2024 grew by 8.6% to $129.6 million from $119.3 million for the full year of 2023, driven by increased revenues from the Company’s accessory and landing gear MRO facilities and higher demand for AerSafe, partially offset by lower sales at its Goodyear, AZ facility.
The gross margin for the full year 2024 was 30.1%, compared to 27.6% in 2023. This increase was due to a favorable sales mix and an overall strong macroeconomic environment, which improved Asset Management margins.
Selling, general, and administrative expenses were $94.2 million for full year 2024 versus $103.2 million for full year 2023. AerSale incurred $4.3 million of share-based compensation expense in 2024, versus $12.1 million in 2023.