WASHINGTON, Feb 12 (Reuters) - JetBlue Airways Corp. filed with U.S. regulators on Tuesday to raise up to $125 million in an initial public offering, two years after the low-cost carrier began operating out of New York's John F. Kennedy International Airport. JetBlue said it intends to use proceeds from the offering for working capital and capital expenditures, including the purchase of aircraft. The New York-based airline did not disclose the amount or price of shares to be offered in its prospectus filed with the Securities and Exchange Commission (SEC). Details are expected in subsequent filings. Amid a lingering economic downturn, JetBlue has managed to buck industry trends by posting profits and expanding service even as most U.S. carriers struggle with the travel slump sparked by the Sept. 11 attacks on the United States. In November, JetBlue reported a third-quarter profit, citing its low-cost business model, even without cash received from the government's bailout of the airline industry. JetBlue, which flies a fleet of new Airbus A320s, initially reduced its flight schedule in the days following the attacks but is now operating more flights than prior to Sept. 11. It recently announced it would buy 10 more Airbus aircraft to bolster its fleet. From New York, JetBlue flies mostly to Florida and to other East Coast cities, along with some service to California and other western destinations. Morgan Stanley, Merrill Lynch and Co., Raymond James, and UBS Warburg are to underwrite the offering, according to the filing. The airline did not say where it intended to apply for a listing.