COLONIE, N.Y. (NEWS10) – A winter storm hitting the mid-Atlantic, combined with the pandemic to further frustrate air travelers whose return flights home from the holidays were canceled or delayed in the first few days of the new year. Upwards of 10 return flights to Albany International Airport were delayed or canceled Monday. This added to a total of over 4,100 flights grounded worldwide.

Southwest Airlines, which services Albany International, had canceled about 575 flights, or 15% of Monday’s schedule, by midday. Spokesman Brad Hawkins said storms over the weekend and on Monday affected operations at some of its biggest airports and left planes and crews out of position. Delta Air Lines issued a travel waiver to let customers reschedule flights to and from Baltimore and Washington.

With the spread of the highly transmissible omicron variant, the seven-day rolling average for daily new cases of COVID-19 in the U.S. has tripled over the past two weeks and topped 400,000 on Sunday, according to figures from Johns Hopkins University. The toll of grounded flights in the U.S. was in the few hundreds per day the week before Christmas, then soared past 1,000 a day, as airlines blamed crew shortages caused by the virus.

Airlines are paying temporary bonuses to encourage pilots and flight attendants to pick up flights left empty by co-workers with COVID-19. United will pay pilots triple their usual wages for picking up open flights through most of January. Spirit Airlines reached a deal with the union to pay flight attendants double through Tuesday.

Travelers could take hope from an improving weather forecast. Airlines canceled fewer than 300 U.S. flights scheduled for Tuesday.

The Associated Press contributed to this report.