Embraer released its fourth quarter of 2021 results, delivering a total of 55 aircraft, of which 16 were commercial and 39 were executive jets (26 light and 13 midsize). The firm order backlog totaled more than $17 billion as of December 31, reaching its highest value since the second quarter of 2018.For the year as a whole, Embraer delivered 141 aircraft, comprised of 48 commercial aircraft and 39 executive jets.During the first quarter of 2021, Embraer delivered the first conversion of a Legacy 450 to a Praetor 500 jet to AirSprint Private Aviation, a Canadian privately held Fractional Jet Ownership company.RELATED: The rare air of the business jet market: When will the oxygen masks drop?Embraer and NetJets, Inc. signed an agreement this year for up to 100 additional Phenom 300, in excess of $1.2 billion. As part of the deal, NetJets will take delivery of the Phenom 300E in the second quarter of 2023, in both the United States and Europe.Earlier this year, in a move to reduce carbon emissions, the company announced its new line of aircraft concepts, the Energia family. The four concept aircraft use different propulsion technologies -- electric, hydrogen fuel cell, dual fuel gas turbine, and hybrid-electric. These aircraft are still just sketched on a drawing board but could be expected to hit the market as soon as 2030.