United Airlines has ordered 30 Embraer 175s with options for up to 40 more of the type with deliveries from 2014.
The aircraft will be configured with 76 seats and will replace older 50-seat regional jets in the Chicago-based carrier's regional fleet. An operator will be announced later.
"At United, we are focused on modernising our fleet, and we look forward to introducing the E-175 to our United Express service," says Jim Compton, vice-chairman and chief revenue officer at United, in a statement. "Compared to the 50-seat aircraft we are replacing, these aircraft provide a superior customer experience and are more fuel efficient."
The move is a reverse of the airline's position in January, when Compton said that it would not order any new large regional jets this year in favour of optimising its existing fleet of regional aircraft. He did say that the airline would consider a move for 2014.
The combined order is valued at $2.9 billion at list prices, according to Embraer. Deliveries will occur in 2014 and 2015.
The E-175s will be laid out with 12 first class, 16 economy plus and 48 economy seats.
United had 345 50-seat jets in its regional fleet at the end of March, according to an investor update on 25 April.