Just like any other deductions you’re going to take on your tax return, aircraft deductions, many of which are direct expenses. You want to keep receipts, you want to keep any invoices, and proof of when that expense was incurred, and how the expense was paid. On top of those traditional documents that you would keep, aircraft also require a flight log, if you’re going to take depreciation deductions and expense deductions. The necessary information for the flight log is defined by section 274. We often encourage aircraft owners, on top of their flight log, to keep a calendar or journal, or other documents that support the aircraft use profile. If there are emails associated with trips, holding on to those emails, or other documentation, just help you show that you’re using the aircraft in the manner in which you say you’re using the aircraft, can be really important tools for justifying the deductions.