Documentary evidence along with proper
recordkeeping are
necessary to support a taxpayer's tax deductions in the event of an
IRS audit.
Publication 463
says that documentary evidence can be in the form of receipts, canceled checks,
or bills, or other approved documents that validate the expense being deducted. The
EZPERDIEM.COM Expense Processor provides a calculating checklist of the various
expenses a flight crewmember might
deduct, along with a printouts that show where the numbers get put on the
crewmember's IRS Form
2106.