By Abhinav Parmar

(Reuters) -U.S. airlines are canceling flights and adjusting schedules with some Florida airports closing in anticipation of disruptions as Hurricane Milton prepares to make landfall in the state on Wednesday.

As of Tuesday afternoon, 1,311 flights within, into, or out of the United States were delayed, and 701 were canceled, with that number expected to rise as more than 1,500 flights scheduled for Wednesday have already been canceled, according to flight tracking data provider FlightAware.

Southwest, one of the largest U.S. airlines, said it was adjusting its schedule at several airports that were pausing operations, including Tampa International Airport and Orlando International Airport.

Orlando International, one of the busiest airports in the U.S., said it would cease operations at 8 a.m. local time on Wednesday, according to a notice on its website, while Tampa International said it was closed on Tuesday.

Allegiant Air, Sun County Airlines and JetBlue Airways are among the carriers most likely to be negatively impacted if Hurricanes Milton and Helene, which hit Florida recently, weigh on travel demand, according to analysts at Raymond James.

JetBlue and Allegiant have canceled 41 and 92 flights, respectively, on Tuesday according to FlightAware, while Sun Country told Reuters it had canceled about 19 passenger flights.

"We expect service to resume later this week, but there are a variety of factors that will go into that decision," Allegiant Air said in a statement.

Hurricane Milton was expected to expand in size on Tuesday as it approaches Florida's battered Gulf Coast, where more than 1 million people were ordered to evacuate.

In response to the expected disruptions, some airlines including United Airlines, JetBlue and Air Canada have added extra capacity to move people out of Florida.

(Reporting by Abhinav Parmar in Bengaluru; Editing by Tasim Zahid and Devika Syamnath)