Low-cost carrier Southwest Airlines Inc. (LUV)'s first-quarter earnings nearly tripled, helped by higher traffic in March, cost cutting and successful financial management of fuel costs.

Quarterly income rose to $76 million, or 9 cents a share, in the January-March period, up from $26 million, or 3 cents a share, last year. Revenue climbed 12 percent to $1.66 billion from $1.48 billion.

Analysts surveyed by Thomson Financial expected Southwest to earn 5 cents a share on sales of $1.65 billion for the period.

"Our rigorous focus on cost reduction and successful fuel hedging program shielded us from record high energy prices," said chief executive Gary C. Kelly.

The company said it was 86 percent hedged for the first quarter, reducing fuel and oil expense by $155 million and enabling it to record a $27 million related accounting gain. Hedging is a strategy to buy fuel in advance at set prices and has paid substantial dividends to airlines that have used it.

Southwest is 83 percent hedged for the second quarter, with crude oil prices capped at $26 per barrel. The airline expects its second-quarter jet fuel costs per gallon to exceed the first quarter's 90.3 cents.

Looking ahead, the carrier is hedged 85 percent in the second half at $26 per barrel; 65 percent in 2006 at $32 per barrel; more than 45 percent in 2007 at $31 per barrel; 30 percent in 2008 at $33 per barrel; and more than 25 percent in 2009 at $35 per barrel.

Southwest said it began the year with weak revenue trends, but that the timing of the Easter holiday in March led to a record monthly load factor of 73.7 percent. The airline said that bookings for May and June are "satisfactory," but that the holiday timing is hurting April traffic and load factors. It is likely that second-quarter load factors will fall short of year-ago record levels, and the company said it is unable to predict whether it will have favorable passenger unit revenue comparisons for the period.

The company expects 2006 available seat mile growth of about 7 percent, based on expected order deliveries.

Shares of Southwest were unchanged at $14.72 Thursday on the New York Stock Exchange (search). The stock has been trading at a 52-week range of $13.18 to $17.06.