Thousands of airline passengers have been left stranded after new Canadian low-cost carrier Swoop failed to get all the regulatory approvals needed for trips to the United States.

The airline has been forced to cancel some of its flights last minute, with flights to the U.S. postponed until October 27 while it waits on authorization.

There are a number of regulatory approvals required prior to operating in the U.S. and all but one operational approval have been received, Swoop said.

A spokeswoman for the airline, which only started operating in June, confirmed to CTV News that 24 flights have been cancelled.

“Our goal is to minimize the amount of overall disruption to our travellers and, after considering a number of factors including rebooking options and aircraft availability, we have leased an aircraft from WestJet to operate many of our flights at the original scheduled departure dates and time,” Karen McIsaac said.

“We are reaching out directly to all affected travellers to acknowledge their situation and to either advise them of their new WestJet flight details or to provide rebooking and/or refund options with compensation.”

Swoop said customers will be offered rebooking on alternate airlines or full refunds plus $100 to $200 in compensation per passenger per travelling segment.

Kyle Wood told CTV Toronto that he and his girlfriend were forced to cancel their anniversary trip to Florida from Hamilton, Ont., instead of paying the significantly higher fees for a new flight.

“We had our bags packed in our living room,” the Etobicoke couple told CTV Toronto. “Now, we’re going to try to make the best of it. We’re going to stay here.”

Wood said he was offered a refund, plus a $100 travel voucher per traveller, each way. He has also received a refund form the hotel where he planned to stay.

“At the end of the day, we’re going to lose memories,” he said.

Fellow Swoop passenger Curtis Stewart didn't think his trip from Edmonton to Las Vegas would be a gamble.

He booked a flight through Westjet, Swoop’s parent company, a year ago to meet his wife to celebrate her 50th birthday, but he received an email two months ago saying his flight was cancelled.

Stewart was one of 32 passengers re-booked to Swoop, but then just two days before departure this flight was cancelled too.

“It just gets me extremely angry that they don’t even have the authority to fly and they’re taking money and booking flights,” he said.

Swoop offers discounted flights throughout Canada and the U.S. and was scheduled to make its first trips to the U.S. this week.

The airline said regular scheduled operations will resume on October 27.

When asked why the airline was selling tickets despite not having full approval, a spokeswoman said it was “common practice in the airline industry.”

“There are a number of sequential steps that go into starting up and launching an airline, including the first step to allow sale of tickets which we had received early on,” she said.

“From there there’s ample lead time to receive the operational certificates needed and in this case unfortunately that lead time wasn’t enough to be able to process.”

Air passenger rights advocate Gabor Lukacs believes this situation is a troubling breach of contract.

"The problem is not just that they don't have the regulatory approval, but rather that they weren't clearly informing the public about it," he told CTV News.

Swoop said that its website includes a notice that flights are subject to government approval.

“We apologize to our travellers for this inconvenience and for the disappointment they have expressed,” Swoop said.

McGill University aviation professor John Gradek added that Swoop made its submission to U.S. authorities this year.

"If it was a WestJet application and it was an extension of existing services that would have been plenty of time," he said.

"Because Swoop was going in there as a new applicant, as a new filing, there's a lot more regulatory hurdles and a lot more approvals that have to be in place for a new carrier to operate in the U.S. From June to October may not have been enough time for the government authorities to go through all of the requirements."

Gradek said customers were taking a risk booking a flight with Swoop after October 27.

"They're counting on getting the authorities in the U.S. to issued issuing the permits needed by next week," he said.

--- With files from CTV Toronto and The Canadian Press