Boeing Co said it had booked two firm orders for its 747-8 jumbo jet, ending what was shaping up to be a second year without net new purchases of the iconic four-engine plane. The orders for the $379 million jet bring to 24 the number of 747-8s Boeing has committed to build, according to Boeing’s official tally. That’s about two years of backlog as the company slows production to one a month in March from 1.3 a month currently. Boeing declined to identify the buyer or say whether the order was for the passenger or freighter version. The company had booked four other 747-8 freighter orders this year, but four cancellations in September had left it with no net increase in the backlog. Boeing is not alone in seeing slack demand for large-four engine commercial planes, which have largely been overtaken by two-engine designs. European rival Airbus’ competing A380 jumbo jet has booked no orders since 2014 from commercial airlines and has 148 orders in backlog. Airbus is considering upgrading the 10-year-old plane’s engines to stimulate sales. Airbus doesn’t make a freighter version of the A380. Boeing has also won a commitment in June for 20 747-8s from Russian cargo airline Volga-Dnepr Group. The U.S. Air Force also agreed to buy an unspecified number of 747-8s for the Air Force One presidential fleet, which currently has two planes. Both need to be confirmed before they would be added to the backlog. Although orders have dwindled, Boeing says at least 143 older 747 freighters will need to be replaced and sees demand for 540 very large aircraft over the next 20 years. Airbus sees a market for 1,551 such planes.