Police say a distress signal went off Wednesday and a chartered aircraft flew to the point of the signal.
People who were on the plane say they saw equipment, but no trace of the men, who had been on skis.
The scientists had been posting updates about their trek on a website.
On Tuesday one of the scientists reported that they were dealing with extremely warm temperatures and could see thin ice in front of them.
A press release from their support team in Holland identifies the men as Marc Cornelissen and Philip de Roo and says searchers saw a dog alive next to a sled near a big hole in the ice.