Another milestone for Southwest Airlines ( LUV).

The airline Tuesday reported strong March traffic figures, including a record load factor for the month.

The low cost carrier said its load factor -- or the number of seats filled -- was 73.6%, up from 67.3% in the year-ago period.

In March, the Dallas-based airline flew 4.7 billion revenue passenger miles, or RPMs, which is one paying customer flown one mile. That measurement of traffic was up more than 15% from last year. Available seat miles, or ASMs, increased 5.4% to 6.4 billion from a year ago.

Southwest also said April and May bookings are "strong in response to recent fare sales."

Southwest shares were up 4 cents at $15.02.

More from Stocks

Finding Stocks Right for You: Cramer's 'Mad Money' Recap (Friday 8/25/18)

Finding Stocks Right for You: Cramer's 'Mad Money' Recap (Friday 8/25/18)

Flashback Friday: Amazon, Chip Stocks, Memorial Day

Flashback Friday: Amazon, Chip Stocks, Memorial Day

Week Ahead: Wall Street Looks to Jobs Report as North Korea Meeting Less Certain

Week Ahead: Wall Street Looks to Jobs Report as North Korea Meeting Less Certain

Dow and S&P 500 Decline, Energy Shares Fall as U.S. Crude Oil Slides 4%

Dow and S&P 500 Decline, Energy Shares Fall as U.S. Crude Oil Slides 4%

Replay: Jim Cramer on the Markets, 10-Year Yield, Oil Prices and Foot Locker

Replay: Jim Cramer on the Markets, 10-Year Yield, Oil Prices and Foot Locker