Passengers with nonrefundable tickets -- mostly leisure travelers -- likely will reschedule their flights.
But if the ash cloud conditions force airlines -- especially those with hubs in the affected European cities -- to cancel flights for a longer period of time, revenue losses from those cancellations will begin to add up and airlines may find it hard to afford their fixed overhead costs, he said.
Assessing the costs of the Iceland ash clouds can be tricky because of the nature of ripple effects. Some of the ripples create economic opportunities.
Airport enterprises such as newsstands and eateries could see a surge in business because stranded passengers likely will be setting up "tent cities" in terminals, Mann said
"It's largely a captive market," he said.
While the airlines lose, ground transportation providers in Europe win. Mann expects European railways, particularly Eurostar, the operator of high-speed trains connecting Great Britain and Europe through the underground tunnel beneath the English Channel known as the "Chunnel," to see an influx of new passengers.
But even Europe's extensive train system has its limits. On its Web site Thursday, Eurostar had a message to travelers: "Due to the disruption to air travel in Europe, Eurostar trains are extremely busy. We would ask that you only come to our stations if you hold a confirmed reservation for travel."
With the air travel shutdowns have come shipping complications. There were concerns Thursday about what would happen to shipments of perishable cargo such as flowers and food, the Associated Press reported.
The world's three major shipping companies all scrambled to adjust operations Thursday.
FedEx released a statement Thursday saying that it was rerouting flights away from Europe's closed airports to open ones and would substitute truck transportation for air shipping. FedEx said its refund guarantee on deliveries "does not apply to delays of this type or nature that are beyond the control of FedEx. "
UPS said that, as of Thursday evening, it was still operating its Cologne, France hub but expected that that hub would be closed today and that the closure of European airspace would affect U.S. shipments.
"As long as European airspace is closed, UPS will be unable to move package volume to and from Europe from the U.S. and Asia," the company said.
For shipments within Europe, the company said, it would "turn to contingency operations and move packages as best we can by ground."
DHL alo said it was expecting "significant disruptions" on several European traffic routes and said it would process shipments in regions affected by the cloud as soon as possible.
While an airline stands to turn a profit off those who have nonrefundable tickets and are unsuccessful in their attempts to rebook, "it's a public relations nightmare," Mann said. "Every single one of [the passengers] is going to understandably whine about it. It's human nature."
--ABC News' Matt Hosford contributed to this report