TORONTO - Porter Airlines has ordered four Bombardier Aerospace Q400 NextGen aircraft worth about US$120 million, plus options for six additional aircraft.

The Toronto-based regional passenger carrier said the value of the order could increase to US$308 million if all six options are converted to firm orders.

"The Q400 aircraft is a foundation of Porter's operation and growth," said Robert Deluce, president and CEO of Porter Airlines.

He noted that Porter started four years ago with two Q400s, which are assembled at Bombardier's Toronto plant, and the airline now has 20 of the aircraft in its fleet.

"We're proud to be one of the world's leading Q400 operators," Deluce said in a news release.

The new Bombardier aircraft are scheduled for delivery in the second quarter of 2011 through the third quarter of 2012, including option aircraft.

Porter also said it raised an additional $15 million in equity from existing shareholders. The proceeds will be used primarily for working capital and new aircraft purchases.

"This equity satisfies Porter's short-term requirements for growth," said Deluce. "At the same time, we expect to determine sources for our long-term capital requirements by the first half of 2011."

Porter Airlines is based at Billy Bishop Toronto City Airport, on one of the islands along the city's lakeshore.

Porter serves Toronto, Ottawa, Montreal, Quebec City, Moncton, Halifax, St. John's, Thunder Bay, Sudbury, New York (Newark), Chicago (Midway), Boston (Logan), and has seasonal flights to Mt. Tremblant, Que. and Myrtle Beach, SC.