Pay later and flight delay
 

Does anyone know if I have my flight number on the reservation and there is a delay if I'll have any problems?
I've read that it's only held for prepaid reservations.
Also is there a phone for the Miami airport branch?

Here is Sixt's official policy. Unofficially, they will typically hold a vehicle for at least a few hours past your scheduled pickup time. It doesn't matter whether it's prepaid or pay-at-counter.

The only number available is the main reservations line -- (888) 749-8227. You can also reach them at [email protected].

Thanks. Guess what I'll do is delay the pickup time before boarding, once I know the time of arrival. Guess I won't have to pay extra to modify to a later time...