It was a travel nightmare that lasted 33 and a half hours.

"Absolutely horrendous," says Betty Clarke.

Clarke and her family were travelling with WestJet, returning from Mexico after a week-long vacation. They left their hotel at 9:00 a.m. Saturday morning, but didn't get home until 6:30 p.m. Sunday night.

It started on Saturday, when passengers on Westjet flight 2841 from Cancun to Ottawa were stuck on the tarmac for four and a half hours. In that time, Clarke says they were offered a glass of water and a bag of pretzels. After the wait, WestJet cancelled the flight for mechanical reasons.

The 150 passengers were taken off the plane and after a three hour wait, were loaded onto buses. They were supposed to be taken to a hotel for the night before flying out the next day. Instead, they were dropped in the parking lot of a hostel, which passengers describe as a "rat hole."

"My 7-year-old grandson got very hysterical because he was petrified he was never going to get home again," Clarke says. "He was throwing up, he was so scared."

Ottawa lawyer Chris Spiteri was also on the flight.

"WestJet seemed to abandon us," he says. Spiteri is considering a class action lawsuit against the airline, on behalf of everyone on the flight.

"It was quite frustrating, seeing kids being sick, kids crying," he says. "What they did was really quite wrong."

WestJet issued an apology to the passengers on Monday. The airline confirms the flight was cancelled because of a mechanical issue and acknowledged that "the service our guests were provided was clearly not up to the WestJet standards that we aspire to deliver."

In a statement, WestJet says passengers were offered accommodation and transportation along with meal vouchers, but "due to an error by our booking partner, some hotel rooms were not available once guests arrived at the properties so some guests were forced to book accommodation elsewhere on their own."

"We understand the frustration these guests experienced and are committed to working with each of them to provide the appropriate reimbursement for accommodation expenses along with a gesture of goodwill for their time and frustration, the statement says.

"WestJet says all passengers were able to depart the following day. It's also in the process of contacting all the passengers affected by the mistake.

Update 6:00 p.m. Tuesday

Westjet has issued a new statement to CTV News Tuesday. The airline says it's conducting a full investigation into what occurred.

It also offered a more detailed explanation of what happened:

"Following the boarding and pushback of the flight, a mechanical issue occurred twice while in the lineup to depart. For the safety of guests      and crew, the issue necessitated a return to the gate for inspection and maintenance both times. With the second issue, guests were informed that the flight would be cancelled. The aircraft was moving almost the entire time, meaning that services like water and snacks could only be offered when it was parked. We do understand how this rolling delay followed by the cancellation was an extremely tough situation for guests to endure."

Some passengers have contacted CTV News, saying WestJet has offered to cover all of their expenses and give them a $100 voucher for a future flight.

Update 9:00 p.m. Tuesday

In an interview with CTV News Tuesday night, the Vice President of Marketing Communications for Westjet apologized again to passengers.

"This was certainly not a shining moment for Westjet and we are sorry for what did transpired," said Richard Bartrem.

"Ordinarily we are good at this sort of thing, unfortunately, this time around, we weren't."

Bartrem went on to explain that the plane was in line for takeoff, when the crew noticed a mechanical issue and turned around. The plane then got in line once more for takeoff, and the same mechanical issue presented itself. The decision was then made to cancel the flight and that's when things went terribly wrong.

"In this particular case there were some crossed wires in terms of what we believed were going to be available rooms for the guests that were inconvenienced with the overnight, and when they got to those hotesl there were not rooms that we expected to be available" said Bartrem.

"We are now together with all the departments involved here at Westjet as well as our third party service provider, going through that full investigation to understand why it was in this case we got this wrong, which we certainly did."

An online Facebook group for passengers of the flight was set up where some members indicated they had received an email from Westjet at around 7:45 p.m. Tuesday night. The email asks passengers to submit their expense receipts and a guest support specialist would contact them.

When CTV asked how compensation would be determined, Bartrem says that all out-of-pocket expenses would be covered, and then it would be determined on a guest-by-guest basis.

Westjet admits to CTV they did not support their passengers the way that they should have and are launching an internal investigation to pinpoint the ways in which they failed their travelers.