The expenses he incurred the first three days of the trip may be deductible business expenses. This guide takes the top corporate travel expense questions and answers them for you.You can deduct travel expenses if they are ordinary (common and accepted in your business) and necessary (helpful and appropriate for your business). This travel expenses tax deduction guide overviews which expenses are deductible, how to deduct them, and how to calculate them. If you travel away from home overnight on business, you can deduct these travel expenses: Airline, train, or bus fares — This includes first-class. The steps below detail how to itemize this meal expense: 1. In your Expense Report, enter the meal expense as pictured below. If you're traveling for business, you can deduct up to half of the cost of your meals as long as they're not "lavish or extravagant."