The 747 begins flying into history

The aviation geek in me is sad to see this happen:

It was a beautiful morning to fly, as Delta Air Lines 9771 broke free of cloudy and cold Detroit and ushered itself into the orangey-pink sunrise waiting just above the drudgery below. The jet, one of the last U.S.-operated passenger Boeing 747-400s, gently lifted off from Detroit Metropolitan Airport several minutes earlier at 7:47 a.m., bound for a rather unusual destination: the Boeing factory from which it was made.

The special homecoming charter flight kicked off Delta’s farewell tour for the original jumbo jet, which will go on to stop in Atlanta, Minneapolis, and Los Angeles this week. It comes as Delta – the last U.S. passenger airline still flying the 747 – winds down its schedule on the aircraft. Delta has only one regularly scheduled 747 flight left – a Seoul-to-Detroit flight that’s scheduled to land Tuesday. 

After that, Delta’s remaining 747s will fly a handful of NFL charters before retiring altogether by the year’s end. With that, nearly 50 years of passenger 747 service with U.S. based airlines will come to an end.

Delta's fleet of 747s originally belonged to Northwest before the two airlines merged, and in fact my very first flight on a 747, from Detroit to Osaka in 2005, was on Northwest (I've since flown on KLM 747s as well). After United retired its last 747 a month ago, Delta was the only domestic airline operating the 747. Now that is coming to an end as well.

It's sad that the fifty-year reign of the iconic and spacious "Jumbo Jet" is seeing its twilight, but it's simply a matter of economics. Two-engined jets are simply cheaper to operate than airplanes with three or four engines:

Today, the industry has moved toward twin-engine planes such as the Boeing 777 and the Airbus A330, with three-engine planes being relatively unpopular because of the high labor costs of working on an engine bedded into the tail fin. 

The four-engine 747 retained a clear place in the market because twin-engine planes must stay within a certain distance from an airport in case of engine failure. 

This allowed the 747 to achieve shorter journey times on the longest routes because it could use more direct flight paths. 

However, improving engine reliability means authorities have slowly increased the distance a twin-engine airliner can fly from a runway, gradually reducing the advantage of having four engines. 

And those newer, more reliable engines have also been bigger and more efficient.

The aforementioned three-engined widebody jets - the DC-10/MD-11 and the amazing and underappreciated Lockheed L-1011 - have long since disappeared from passenger service. Four-engined widebodies - the Airbus A340 and the double-decker Airbus A380 as well as the 747 - have been able to continue in service because of their range and capacity advantages over their two-engined counterparts. 

However, the gradual relaxation of ETOPS requirements, as well as the fact that two-engined jets can land at smaller airports than their four-engined counterparts are therefore more flexible to airlines wanting to provide specific non-stop long-haul routes, have cut into the usefulness of the 747 such that fewer and fewer airlines think it makes economic sense to replace the 747s reaching the end of their service lives with new ones. This is why domestic carriers like United and Delta have phased the 747 out of service; they feel it makes better business sense to replace their four-engined aircraft with advanced two-engined ones such as the Boeing 787 Dreamliner. 

This is not to say that the 747 is immediately disappearing from the skies; it will continue in service as charter aircraft, as cargo freighters, and in the fleets of foreign carriers. Boeing is still building 747-8 aircraft (although orders are understandably slow); newer 747s still have a good two decades of service ahead. 

But otherwise, time marches on. The Boeing 747's importance to America's passenger aviation industry has, after many decades, come to an end.