We disagree.
IRS rules Sec. 162 permits deductions: "[t]here shall be allowed as a deduction all the ordinary and necessary expenses paid or incurred during the taxable year in carrying on any trade or business...."
IRS rules and the Courts have ruled on ordinary and necessary and have included in these expenses travel by air. See Marshall v. Commissioner, 1992.
The only remaining question is what is reasonable? The Tax code is silent on this but the courts are not. Automobile operators/owners are permitted but not required to deduct all maintenance, acquisition (depreciation/Sec 179 expense), and operating expenses. Or they can take the standard mileage rate, which reimburses them at a lower rate than if they did the above.
So, what is reasonable? The GSA mission is to operate the government efficiently and provide its agencies among other things, office space, supplies and equipment, and transportation as economically as feasible and this includes the IRS. It has for this purpose established a schedule of reimbursement for privately owned vehicles, which the IRS conveniently uses for determining a shortcut for deducting automobile expense. The tax code does not mandate how I determine a reasonable expense, as far as I can see, and I am permitted by Section 162 to deduct it as long as it meets the above tests, including reasonableness. I claim the GSA POV standard mileage rate meets the reasonableness test, although I do not know their methods, I do know their rate understates my actual operating costs, let alone the rest of the package.
If the IRS were to argue and disallow a deduction based on the GSA recommended rate for aircraft, it would also face the very real argument that it must likewise disallow the deduction based on the per mile rate for automobiles, which would be to the tax payers advantage in that most automobiles will be able to claim a greater deduction than the standard mileage rate, at the expense of tens of hours, if not more, of additional paper work/record keeping each year.
If the IRS were to dispute the GSA POV recommendation, then there would be no problem with me or like situated taxpayers simply amending my old 1040/Sched C's to use the other method, and after paying an accountant to do this, I might make enough to buy a cup of coffee from the additional refund, or maybe a new coffeemaker that grinds its own beans. The IRS, on the other hand will spend a lot more time on my return and TurboTax would make more money by requiring me to buy an more sophisticated version.
