June 27 (Reuters) – Airlines canceled over 700 flights in the United States on Monday, as adverse weather and a shortage of staff hurt their ability to keep up with a surge in summer travel demand.

Total flight cancellations within, into, or out of the United States as of 1.07 p.m. ET were 747, as per flight-tracking website Flightaware.com. Nearly 860 flights were canceled on Sunday.

Delta Air Lines had over 200 cancellations, Republic Airways Inc and United Airlines Holdings Inc had 196 and 122 flight cancellations, respectively, while American Airlines Group Inc canceled 62 flights as of Monday afternoon.