US Airways reported on Wednesday that its net income doubled in the fourth quarter from a year earlier, and its executives said strong passenger demand for the airline could lead to higher fares.

Fewer empty seats made the difference in the last three months as revenue set a record.

Airlines successfully raised fares five times last year but have struggled to do so lately. Two attempts led by United Airlines this month failed after other airlines did not match the increases. For US Airways, one measure of fares, called passenger yield, the average fare paid per mileage, declined slightly in the fourth quarter.

The US Airways president, Scott Kirby, noted that full planes and improved demand typically lead to fare increases. There were fewer empty seats in the final quarter of 2012 — occupancy rose 2 percentage points to 83.9 percent. January bookings are up 8 percent from a year ago, Mr. Kirby said.

“While it’s taking some time, I expect that this strong environment will lead to improving yields across the industry,” Mr. Kirby said in a conference call with analysts.