Low-cost carriers Southwest Airlines Inc., JetBlue Airways Corp. and Independence Air on Thursday reported upbeat October passenger traffic figures, signaling greater demand for air travel and lifting airline stock prices.

The sector was also buoyed by a drop in crude oil prices Thursday on the New York Mercantile Exchange. Prices for a barrel of benchmark crude for December delivery declined $2.06, to $48.82. The American Stock Exchange Airline Index closed up 4.8 percent Thursday.

Southwest and JetBlue reported sharp gains in passenger traffic -- expressed as revenue passenger miles, or one paying passenger flown one mile. Southwest said its traffic grew 12.5 percent from the previous month, to 4.5 billion revenue passenger miles, while JetBlue's traffic rose 33.7 percent year-over-year, to 1.4 billion revenue passenger miles.

Dulles-based Independence Air, owned by Flyi Inc., said it flew 213.9 million revenue passenger miles in October, a gain of 22 percent over the previous month.

But increases in capacity at both JetBlue and AirTran Airways outpaced growth in traffic. The two were the only low-cost airlines that saw load factor, or overall plane occupancy, decrease last month.

JetBlue's total capacity increased to 1.68 billion available seat miles in October from 1.52 billion in September, as AirTran's capacity rose 18.2 percent, to 1.06 billion available seat miles. AirTran's October traffic jumped 16.1 percent year-over-year, to 716.1 million revenue passenger miles. Load factor at JetBlue was 83.1 percent, down from 85.5 percent a year ago, while AirTran's occupancy fell to 67.8 percent from 69.1 percent last year.

Southwest boosted its capacity by 8.4 percent, to 6.76 billion available seat miles in October, and said its 66.6 percent occupancy rate for the month gained 3 percentage points year-over-year.

Independence said its total capacity rose 6.35 percent, to 388.5 million available seat miles. Its October occupancy was 55 percent, up from 48 percent last month. The news comes as a welcome change after analysts had expressed concerns about the performance of the carrier, which began flying in June.