Two major commercial air carriers are planning to begin nonstop seasonal service between Key West and both New York City and Washington D.C. in time for the Christmas travel season. Delta Airlines says it will offer direct flights from New York's LaGuardia Airport Dec. 22, 29 and Jan. 5; and each Saturday from March 2 through April 6. Officials say the 1,211-mile flight will be longest commercial route ever to serve Key West. Direct U.S. Airways flights from Washington's Reagan National Airport will be offered once daily Dec. 22 through Jan. 5, and continue each Saturday through April. Also adding flights is Southwest, with plans to provide daily service between New Orleans and Key West beginning March 9.