Shares of

Continental Airlines

(CAL) - Get Report

jumped Thursday after the airline reported strong May revenue that could put it on track for a second-quarter profit.

On Wednesday night, Continental said mainline unit revenue, measured in revenue per available seat mile, or RASM, increased between 9% and 10% last month from a year ago. The mainline figure excludes regional flights. In April, mainline RASM improved 2.4% from a year before.

Shares rose 94 cents, or 7%, to $14.51.

The performance exceeded analysts' expectations. J.P. Morgan's Jamie Baker, for example, was predicting a 7% gain.

"RASM of this magnitude all but assures a second-quarter profit despite surging energy costs," Baker wrote in a research note after Continental's report. His firm does and seeks to do business with companies covered in its research reports.

For the time being, Baker is sticking to his estimate that Continental will earn 15 cents a share in the second quarter. Other analysts, however, tweaked estimates in the wake of Continental's announcement, causing the Thomson First Call consensus to improve to a loss of 10 cents a share by midmorning Thursday. On Wednesday, the consensus was for a 39 cent-a-share loss.

A quarterly profit -- which would require a strong June performance from the carrier -- would be welcome news in an industry that recently has suffered huge losses from historically high fuel costs and overcapacity.

Continental said the principal factor behind the surge in unit revenue was a better load factor, which measures the percentage of seats filled on planes. The airline's mainline load factor was 79.8% last month, up 5.1 percentage points from a year before and a record for the month of May.

Unit revenue also benefited from a recent series of domestic fare increases instituted by major carriers, Continental said.

The airline's fuller planes came as mainline passenger traffic jumped 9.8% from a year ago, more than offsetting a 2.8% increase in capacity.