U.S. airlines on Thursday began to cut flights at East Coast airports and made plans to move aircraft from the region due to approaching Hurricane Irene.

Major airlines encouraged travelers to consider changing flight plans or postponing trips with the massive storm threatening to sweep north through mid-Atlantic and Northeastern states over the weekend.

Airlines affected include Southwest Airlines, US Airways, Delta Air Lines, American Airlines and United Airlines.

Most waived fees for rebooking tickets.

Shares fell 3.5 percent on the Amex Airline Index markets. Those with service to the Caribbean, where Irene lashed the Bahamas with 115 mph winds, took hard hits on Wall Street.

Jetblue Airways, which is based at New York's Kennedy airport, shed more than 7 percent. US Airways was off more than 4 percent and Delta, 5.7 percent.

Southwest, American and United also ended lower.

New York-area air space is the most congested in the United States, and Irene threatened the region at the busiest time of the year for airlines.

Cancellations and delays in the East affect flights across the country and overseas, prompting advisories of more widespread delays.

Irene threatened air service just two days after an earthquake centered in Virginia disrupted travel along the eastern seaboard.

Separately, U.S. passenger railroad Amtrak canceled most train service south of Washington for Friday, Saturday and Sunday due to potential affects of the storm.

Most trains in the heavily traveled Northeast Corridor between Boston, New York and Washington are not currently affected, Amtrak said.