MADRID, May 13 (Reuters) - Spanish construction giant Ferrovial posted a 37.6% rise in first-quarter core earnings on Monday, a few days after its shares debuted on the Nasdaq in the United States, the country where it makes most of its revenue and investments.

Ferrovial's adjusted earnings before interest, taxes, depreciation and amortisation (EBITDA) reached 254 million euros ($274.02 million), in line with average analysts' expectations of 253.4 million euros.

The 3.5% increase in revenue to 1.88 billion euros slightly missed the 1.91 billion euros forecast by analysts polled by LSEG.

The company's strong results are mainly due to higher income and strong traffic growth at its toll roads in North America as well as to the performance of its construction businesses.

At one of the highways it operates in the United States, the Express NTE 35W in Texas, revenue rose 72.8% compared with the first quarter of 2023 on a 45% increase in traffic, the company said.

In the United States, all express lanes revenue grew above inflation.

Ferrovial is looking to expand in the U.S., which accounts for around 80% of its toll road revenue, by gaining greater recognition and liquidity on the stock market. The infrastructure builder is the first firm listed on the Spanish stock market index to trade on the Nasdaq with ordinary shares.

Ferrovial expects to focus on more opportunities to build and manage highway lanes and airports around cities in the southeastern U.S. and also around New York, CEO Ignacio Madridejos told Reuters last week. The company plans to allocate at least 80% of all its investments to this market until 2027.

The company, which is building a new terminal at New York's John F. Kennedy International Airport, is expecting to sell a 25% stake in Heathrow Airport, Britain's busiest airport, by the end of 2024, subject to regulatory conditions.

Dealmaking in the European airport sector is picking up, as a few weeks ago Vinci Airports bought a 50.1% stake in Edinburgh Airport.

Ferrovial also operates the Aberdeen, Glasgow and Southampton airports in Britain, which increased its traffic by 8.4%. ($1 = 0.9270 euro) (Reporting by Corina Pons in Madrid Editing by Pietro Lombardi and Matthew Lewis)