Atlanta-based Delta Air Lines estimates Hurricane Sandy snagged away $45 million in revenue and will ultimately amount to a $20 million hit to the carrier’s bottom line for October.

Delta canceled more than 3,500 flights last month in response to Sandy, amounting to a 2 percent reduction in its flying. The storm’s impact also will spill into November, but it’s expected to result in a smaller toll than in October.

The airline has a hub at New York’s John F. Kennedy International Airport, is building a domestic hub at New York’s La Guardia Airport and employs 7,000 in New York. Delta is still recovering from the disruption Sandy wrought. It operated close to its full schedule at JFK and Newark on Thursday, but only about 80 percent at La Guardia. The airline was expecting to resume its full operation at La Guardia on Friday.

Meanwhile, Delta’s foundation donated $100,000 to the American Red Cross to help with Hurricane Sandy relief, and said it has long given free seats and cargo space on planes for the movement of supplies and workers to and from disaster areas during relief efforts.