Can I ask for a travel advance?

Yes. If your travel costs exceed € 500,- you can ask for an advance payment (Reisekostenvorschuss) for your spendings. (€ 500,- is also the payment's minimum amount.)

In this case, the travel request has to be submitted and approved at least one month before the trip. Furthermore, reimbursement must happen through the app "Travel accounting" afterwards.

Travel advances are not possible when filing a Leave of Absence.