TAMPA, Fla. (WFLA) — Hundreds more flights were canceled on Sunday, one day after major airlines announced nearly a thousand flights were canceled across the nation.

Airlines said the fast-spreading omicron COVID-19 variant has had a direct impact on flight crews and the people who run the airline’s day-to-day operations.

As of 9 a.m. on Sunday, FlightAware shows 643 total cancelations within, into, or out of the United States. At Tampa International Airport, there were five cancelations and 13 delays.

Sherb Macclary came to Tampa to spend Christmas with his family. When he checked the status of his return flight back to South Carolina before leaving for TPA, it was on time.

“The flight was canceled without knowledge,” said Macclary. “There was no warning and there was quite a few of us that were surprised when we got to the gate and found out the flight was canceled and didn’t get notified at all.”

Macclary was left stranded. His once-direct flight on Silver Airways back home has turned into several hours of waiting for his new United flight that connects him through Dallas.

“Had we known prior to coming to the airport, we could’ve made other arrangements, but getting to the ticket agent and then being told that at that moment that the flight was canceled – that’s annoying.”

Connecting flights and return flights are up in the air as it’s unclear how much omicron will affect flights moving forward leaving thousands of travelers frustrated.

On Christmas, FlightAware showed 996 cancellations and 3,161 delays. Delta cancelled 310 flights, United cancelled 240 flights, JetBlue cancelled 126 and American Airlines had 97.

According to the Transportation Security Administration, on Christmas day 1,533,398 million travelers went through TSA checkpoints. This is up from last year where 1,128,773 went through checkpoints.

Just days ago, Delta’s CEO called on the CDC to cut the length of COVID-19 quarantine in half for vaccinated employees from 10 days to five to jumpstart the industry and prevent further disruptions.