The summer of air travel chaos continued with almost 900 flights cancelled and 6,500 delayed on Sunday

Over 6,500 US flights were also delayed on Sunday as travel chaos hits the airline industry.Airlines are battling pilot shortages and delays as travel returns to pre-pandemic levels.

More than 800 flights across the US were cancelled on Sunday, according to data from flight tracking website, FlightAware, as 2022's summer of travel chaos continued at speed.

Delta canceled 235 flights, while Southwest Airlines canceled 105 flights, and American Airlines canceled 104 flights, according to the data.

Over 6,500 US flights were also delayed on the same day, per FlightAware.

Travel disruptions have escalated throughout the busy summer period, as airlines have trimmed their flight schedules or canceled operations to cope with staff shortages, delays, and surging demand for travel.

The situation has been particularly disruptive over holiday weekends. US airlines canceled or delayed more than 35,000 flights over the Juneteenth and Father's Day weekend.

The cancellations are causing chaos at airports across the US, as demand for travel returns to levels seen before the pandemic.

Airlines are grappling with pilot shortages caused by thepandemic and are now struggling to recruit and retain the numbers needed to keep up with travel demand.

United Airlines has also cited a shortage of air traffic controllers as a reason for the disruptions. The airline recently cut 12% of its schedule from Newark Airport hub to avoid delays.

Other airlines have also preemptively slashed their summer schedules to avoid delays, including Alaska Airlines and JetBlue.

A spokesperson for Delta told Insider that "higher-than-planned unscheduled absences in some of our work groups, weather and air traffic control constraints," affected flights over the weekend.

Southwest Airlines attributed the situation to "thunderstorms along the Eastern seaboard, especially around the northeast and mid-Atlantic regions, which resulted in route constraints and air traffic control programs," according to a Spokesperson.

A travel analyst previously told Insider that bad weather and the upcoming hurricane season threatens to worsen the situation.

American Airlines did not immediately respond to requests for comment from Insider outside normal business hours.