I filed and got paid for a travel voucher by the Air Force in November 2016 for a trip I had done in 2015. How should I report that income since I see no W-2 for it?

What kind of travel was it? PCS or TDY?

TDY

and unless I'm mistaken, you still get to keep any frequent flyer miles.

Great, thanks for the heads up!

You do not report military travel voucher payments on your tax return.

Payments received for military temporary duty travel (TDY) are not treated as income. They are simply reimbursements for work-related travel expenses.