(CNN) -- It's one thing to lose your luggage while flying. It's another when your dog goes missing.
Josiah Allen says his dog, Paco, didn't make it home when he flew recently from Mexico to his home in Seaforth, Canada.
Delta Air Lines says the dog escaped from a carrier on the tarmac.
"I am hopeful that Delta will be able ... to locate and retrieve Paco and that he can come to my home and be loved and cared for," Allen said.
A Delta spokeswoman, Susan Elliot, said Paco broke out of a dog carrier at the airport in Mexico City, Mexico, on May 3.
"Our staff have conducted exhaustive searches to locate the dog," she said.
They have not found Paco.
Delta has offered its "sincere apologies that we have been unable to recover the dog," Elliot said. The airline has compensated Paco's owner and offered to reimburse all expenses associated with the dog, she said.
A Delta representative at the Mexico City airport told Allen that Paco's dog carrier was too small, Allen said. He said Delta asked him to sign a waiver saying the airline would not be liable for any injuries that Paco might suffer as a result of the carrier's size.
Allen said he signed the waiver because Paco had slept in the crate for three nights with no problems.
"He could both turn around and stand comfortably," he said.
Yet when his plane landed in Detroit, Michigan, Allen said, the dog was gone.
The story of Paco's disappearance unfolded not long afterward on a blog called The Consumerist, which says it "empowers consumers by informing and entertaining them about the top consumer issues of the day."
Elliot said she couldn't recall another instance when a dog got lost while its owners were in transit.
"This is extremely rare," she said.
CNN's Jamie Guzzardo contributed to this report.