Imagine the Avios...

All our military aircraft fly with a collection of fuel credit cards and you normally just fan them out in front of the bowser driver and see which one he takes for payment. For dire situations there's usually a cash imprest held with US dollars (and some other major currencies, but everywhere loves dollars) but this is usually for feeding the crews at the local restaurants. It wouldn't be the first time I've seen it considered for use as payment when a bus driver refused to take everyone to the airport as he hadn't been paid, before his boss rang him and told him to stop being an idiot and just drive us...