The Fly America Act states that all U.S.-government funded travel must be done via U.S. air carrier service (there are some exceptions, but none of them apply to my scenario). I recently received a travel grant from my university, independent of any government research funds, and I know that I am allowed to fly non-U.S. carriers with that university travel grant money. However, the grant does not cover all of my expenses for this trip, and I wanted to use government funds to cover the remaining.
Can I fly on non-U.S. carriers and pay for the flight portion of the travel costs using the university travel grant? Would there be any issues with this? To reiterate, I would only use the government research funds to cover non-flight portions of the travel.