The Boeing 747's slow descent into retirement from commercial service just got steeper with British Airways' announcement Friday it would be pulling the jumbo jet from the skies as the coronavirus pandemic forces it to cut back operations and cut costs.

BA's announcement follows moves by a number of other airlines that have retired their 747s and their Airbus A380, another jumbo-sized four-engine jet made by Boeing's European rival.

The fact the planes have four engines means they consume more fuel, which means they can cost more to operate and cause more pollution if not full. 

Who has grounded their jumbos? 

Lufthansa announced in April that it is grounding five of its 32 747s and 14 A380s, saying the move was related to their higher environmental and economic footprint.

Air France, which had already planned to retire its A380s in 2022 because of their higher operating costs, also took advantage of the reduced demand for traffic due to coronavirus lockdowns to mothball them early.

Australia's Qantas also accelerated its phase out of its three 747s, and its A380s are also set to go.

Korean Air is only flying 12 out of its 23 Boeing 747s -- 11 cargo and one passenger jet, according to the airline.

Air India's four 747s are being used to fly VIPs and take part in evacuations.

America said goodbye to the Boeing 747 in December 2017, when Delta, the last US airline to use the jet, retired the aircraft. 

Coronavirus to blame?

"Coronavirus is an accelerant," said Remy Bonnery, an aviation expert at Archery Consulting.

Both the 747 and A380 "are much more difficult to manage in a fleet... They are not the easiest aircrafts to fill, they consume more" fuel, he said.

Launched in 1970, Boeing's jumbo jet can transport more than 600 passengers in certain configurations. The A380 can carry up to 853.

"Even before the crisis there was a trend towards smaller and more flexible aircraft" that are less costly to operate and can be used very different types of routes, said Bonnery.

Aviation expert Sebastien Maire at Kea & Partners recently told AFP that the A380 offers airlines the lowest operating cost per seat, provided every seat is occupied. 

Filling the planes was proving difficult for airlines on many routes, however.

- End of the giants of the skies? - 

"It is clear there won't be trend towards jumbos in the coming years," said Bonnery, adding that the "manufacturers will above all focus on short-haul planes and single-aisle aircraft capable of assuring long routes."

Emirates, which has the largest fleet of A380s at 115, has said it will continue to fly the aircraft that entered service just 15 years ago.

But Emirates acknowledged that the days are numbered for jumbo jets.

Airbus has already announced it will make the final delivery of a 251st A380 next year.

Bloomberg reported earlier this month that the final 747 will roll off the assembly line in two years, but the manufacturer has yet to officially confirm when it will halt production.

There is one customer still waiting for delivery of new 747s: the White House. 

Two of the latest version the aircraft, the 747-8, the largest, fastest an most fuel efficient version of the aircraft are due to made to serve as Air Force 1.