Bristol University Professor Martin Birchall, a voice specialist and ear, nose and throat surgeon, said he had to pay more than $20,000 for a private jet to Barcelona, Spain, after easyJet staff refused to allow him and his team to take the stem cells, which were being carried in a protective liquid, The Daily Mail reported Thursday.

Birchall said the last-minute denial, which came after months of double-checking to ensure the cells would be cleared for transport, nearly stopped the team from arriving in Spain soon enough to perform the world's first windpipe transplant.

"We thought about driving to Barcelona but that would have taken too long," Birchall said. "If we hadn't been able to get the cells there, we would have wasted years of work and this major breakthrough for surgery and science wouldn't have taken place."