SAO PAULO (Reuters) - LATAM Airlines' share of Brazil's domestic market reached its highest level in 11 years in March, data from local aviation regulator ANAC showed on Monday, while rival Gol continued to falter after filing for bankruptcy.

The Brazilian unit of Chile-based LATAM had a market share of 41% in the month as defined by revenue passenger-kilometers (RPK), according to ANAC figures, which the firm said was its highest since the 41.6% reached in July 2013.

LATAM has been leading the domestic segment in Latin America's largest economy since 2021, when it overtook Gol, which in turn has seen its market share decline since entering bankruptcy proceedings in January.

Brazil's once leading carrier had 29% of the domestic market in March, with its RPK dropping 13.4% on a yearly basis, losing the second place to rival Azul ( AZUL ), which hit 29.5% after a 6.7% year-on-year growth in traffic.

Gol, which has struggled with heavy debt load and delays in deliveries by planemaker Boeing ( BA ), filed for Chapter 11 bankruptcy protection in the United States earlier this year to restructure its debt.

LATAM itself came out of pandemic-related bankruptcy proceedings with an $8 billion reorganization plan in late 2022 and resumed growth afterwards, while Azul ( AZUL ) had to conclude a broad debt restructuring last year.

"In 2024, LATAM expects more aircraft to be delivered and fresh growth of 7% to 9% in its domestic operations in Brazil," the carrier said in a statement. "In practice, more than 3 million company seats will be added in the country this year."

LATAM's traffic as measured by RPK grew 11% in March from the previous year.

At the end of last year, LATAM had 37.8% of Brazil's domestic market, while Gol and Azul ( AZUL ) stood at 33.3% and 28.4%, respectively.

Azul ( AZUL ) recently bumped up its estimate for core earnings in 2024, saying demand has been healthy and more routes are expected to be added this year. According to ANAC, total demand for air travel was up 1.4% in March from a year earlier.