According to state guidelines, a traveler may be reimbursed for mileage when traveling out of state if the cost is less than flying. A cost comparison, along with supporting documentation, must be included with the expense report. The expenses that should be used for this comparison are:

1. The cost of roundtrip airfare

2. The cost of airport parking for the duration of the trip

3. Personal car mileage for roundtrip from the traveler's residence or headquarters (the closer of the two options) to the airport. 

If the cost of flying is less than the cost of driving, then the traveler will be reimbursed the amount it would have cost to have flown. Please use the cost comparison form found here: Cost Comparison Worksheet