Brazilian manufacturerEmbraerdelivered21 commercial aviation aircraft in the first-quarter of 2016, a 5% increase over the year-ago quarter.

Nineteen of the delivered aircraft were E175 models, including six to American Airlines, four each to US regional carriers Republic Airlines and Mesa Airlines, three to US regional carrier SkyWest Airlines, one to KLM Royal Dutch Airlines’ regional subsidiary KLM Cityhopper and one to Suzuyo & Co., the parent of Japanese domestic carrier Fuji Dream Airlines. Additionally, China’s Hainan Airlines took delivery of two E195s.

Embraer did not report any new orders for the first quarter, yet on April 12, Alaska Airlines’ Portland, Oregon-based regional subsidiary Horizon Air placed a firm order for 30 E175s, plus options for an additional 33 E175 aircraft. If all options in the order are eventually exercised, the total value of the transaction will be $2.8 billion at current list prices. The order is the largest order ever placed by Horizon Air.

As of March 31, Embraer’s firm order backlog totaled $21.9 billion in aircraft, down $600 million from the 2015 close-out. Embraer’s backlog has a queue of 492 aircraft comprising 150 E175s, 100 E175-E2s, 90 E195-E2s, 77 E190-E2s, 55 E190s, 17 E195s and three E170s.