Airlines keep slashing flights due to staff sickness caused by COVID-19. More than 2,200 flights have already been canceled for Wednesday.

• Airlines are slashing flights for a sixth consecutive day, citing staff sickness and bad weather.
• Among US airlines, United and SkyWest had the highest number of cancelations on Wednesday.

Mass flight cancellations have hit travelers for the sixth consecutive day amid rising levels of airline staff sickness and bad weather in parts of the US.

As of Wednesday morning, 2,212 flights set to depart that day had been canceled, according to figures from the flight-tracking website FlightAware. Data from the website suggests that about 15,000 flights have been canceled since Friday morning.

Of Wednesday's cancellations, 714 — just under a third — were flights within, into, or out of the US, according to FlightAware's data at the time of writing.

United Airlines has canceled 153 flights, or 7% of its total flights for the day, according to the data.

Alaska Airlines has canceled 74 flights scheduled for Tuesday, or 11% of its flights, and JetBlue has canceled 78 flights, or 7% of its schedule.

Delta has canceled 88 flights, or 3%, and Spirit has canceled 56, or 7%.

SkyWest, which is contracted for some regional flights by Alaska, American, Delta, and United, has canceled 144 flights on Tuesday, or about 6% of its scheduled flights.

American Airlines and SkyWest previously told Insider that they had canceled some flights due to rising cases of COVID-19 among staff. A Delta spokesperson said the Omicron variant had affected the airline's schedule. The variant is now the dominant strain in the US.

Delta, Alaska, and SkyWest said that harsh weather conditions in parts of the US, including heavy snow in Washington state on Sunday, were also to blame for some cancellations.

More than 150 flights arriving in or departing from Seattle were canceled Tuesday, or 24%, and just under half of the flights that went ahead were delayed, per FlightAware data. Almost 200 flights set to arrive in or depart from Seattle-Tacoma on Wednesday were already canceled as of Wednesday morning.

The bulk of Wednesday's canceled flights were operated by Chinese airlines, including China Eastern, which has canceled 441 flights, or 21%, and Air China, which has canceled 207 flights, or 17%.

Xi'an, a city in central China with around 13 million residents, entered a strict lockdown on December 23 amid a sudden surge in coronavirus cases. As of Wednesday morning, 19% of that day's flights to Xi'an Xianyang International Airport and 21% of flights from the airport had been canceled, per FlightAware data.

The Indonesian airline Lion Air has also canceled 109 flights, or 22% of its schedule for Wednesday.

The three airlines didn't respond to Insider's requests for comment.

Airlines have been canceling flights since Christmas Eve

On Tuesday, 3,129 flights were canceled, including 1,291 departing from or arriving in the US, and 14,513 flights were delayed, with just under half of these departing from or arriving in the US.

Among US airlines, SkyWest had the highest number of cancellations on Tuesday, canceling 362 flights, or 15% of its schedule, and Horizon had the highest percentage of its flights canceled, at 24%, per FlightAware data.

Airlines canceled about 3,300 flights on each of Sunday and Monday, with almost half of these departing from or arriving in the US, according to FlightAware data.

Airlines also canceled at least 4,200 flights across Christmas Eve and Christmas Day.

It's not just airlines being affected by rising COVID-19 cases. The New York City Transit Authority said on Sunday that subways would be less frequent because of the COVID-19 surge, which had caused staff sickness. The CDC is also investigating or observing almost 90 cruise ships amid COVID-19 outbreaks