WATERTOWN, N.Y. (AP) — The U.S. Department of Transportation has extended the deadline to Feb. 29 for air carriers to submit proposals for providing federally subsidized air service to Watertown, Massena and Ogdensburg.

Gulfstream International Airlines of Fort Lauderdale, Fla., had requested a two-week extension from Friday's deadline. The extension applies to all carriers, including Cape Air of Hyannis, Mass., which began providing essential air service Tuesday to Plattsburgh and Saranac Lake.

The three northern New York communities were left without commuter air service last month when Montana-based Big Sky shut down its East Coast operations because of disappointing revenues.

In mid-January, federal regulators approved Cape Air's $2.8 million bid to provide essential air service to Saranac Lake and Plattsburgh but rejected a $5.5 million bid from Boston-Maine Airways to serve Watertown, Massena and Ogdensburg. The agency said it was concerned with the high cost of providing service and whether the Portsmouth, N.H.-based airline could afford the expansion.

Cape Air provides flights in the New England region, Indiana, Florida, the Caribbean and Micronesia using mainly nine-seat Cessna 402s. The airline, which has operated since 1989, uses Boston's Logan International Airport for its Northeast hub. The air carrier operates as a JetBlue partner on several Northeast routes.

Cape Air spokeswoman Michelle Haynes said the airline was ready to submit a bid regardless of the deadline extension.

Gulfstream, which operates flights in Florida and the Bahamas, is looking to expand into the Northeast market. The airline, which primarily uses 19-seat turboprop aircraft, has code-share agreements with Continental, United and Northwest airlines. A code-share agreement with a major airline allows passengers to book flights with either carrier via a single ticket.

Mickey Bowman, Gulfstream's vice president of corporate development, said his airline would need to develop other Northeast routes to make it feasible to serve upstate New York. The airline hasn't decided whether it would submit a proposal for the route but plans to visit the North Country airports this week, he said.