United Airlines, the third-largest U.S. carrier, plans to add lucrative flights between smaller cities this year as it targets higher profitability and growth after a $192 million benefit from the Republican tax overhaul.

Following the 2010 merger between United and Continental airlines, the company had trimmed regional flights and emphasized routes connecting larger markets like Newark and Atlanta where competition was fiercer and margins were lower, President Scott Kirby told investors on an earnings call Tuesday. Today, about 26 percent of its business comes from smaller, higher-yield markets where rivals like American and Delta draw 30 percent to 40 percent.

"We did this to ourselves," he said. "One of the key elements for driving higher revenue at United is getting us back exposed to our fair share of these markets that we pulled out of over the past five or six years."

The Chicago-based carrier expects to add 31 smaller jets from Embraer and Bombardier, taking its regional fleet to 549 aircraft, according to a presentation. Doing so will drive up cost per mile flown, conceded Chief Financial Officer Andrew Levy, but "that's what it's going to take to fix our network" and buoy profitability.

United is targeting profit growth of as much as 21 percent this year, taking earnings as high as $8.50 a share, and as much as 85 percent by 2020.

"We feel like we can deliver on these numbers in 2018," Chief Executive Officer Oscar Munoz said on an earnings call, "and we want to deliver."

Earnings of $1.99 a share in the three months through December compared with the $1.34 average from analysts surveyed by FactSet. Net income climbed 46 percent to $580 million on total sales of $9.44 billion, the company said in a statement.

Its tax rate will probably be about 24 percent in 2018, compared with 29 percent last year, when it was trimmed by the tax overhaul that Congress approved in December. Among other provisions, the law trimmed the top corporate rate to 21 percent from 35 percent as President Trump works to fuel more rapid U.S. economic growth.

United's shares dropped 6.5 percent to $77.97 after the close of regular New York trading on Tuesday as executives predicted a flat profit margin in the first three months of this year.

The stock's gain of 3.6 percent in the past 12 months trailed a 25 percent rise by the broader S&P 500.