UPS Airlines has ordered 14 more Boeing 747-8Fs to double its future fleet of the re-engined jumbo freighter and add vital months, perhaps even years, to the type's backlog.

The cargo airline has also ordered four more 767 freighters, it disclosed in separate announcements on Twitter today.

The orders were revealed as UPS released annual earnings showing strong growth in 2017 and expectations of higher demand this year.

"These [747-8Fs] will provide additional capacity in response to accelerating demand for our air services," UPS says on Twitter.

UPS has almost single-handedly kept the production line for the 747-8 alive in Everett, Washington.

The carrier placed an order for 14 747-8Fs in October 2016. That order represents 11 of the 12 orders remaining in Boeing's backlog for the widebody type. Boeing has slowed output on the 747-8 production line to delivering six aircraft per year.

With the new UPS orders, Boeing now has as many as 25 747-8Fs in the backlog, depending on how many new orders and deliveries there were in January.

Boeing's goal has been to keep the 747-8 production line alive through at least 2019. The manufacturer expects a wave of new demand for the 747-8F as large fleets of 747-400Fs and MD-11Fs reach retirement age.

In addition to replacement demand, the air freight market has begun to show signs of sustained growth after a long period of decline and stagnation, which began just as the 747-8F entered service in 2010.

Source: Cirium Dashboard