Recently I encountered someone traveling in the Northeastern U.S. who claimed to be the only revenue passenger on an early-morning flight of a U.S. major carrier; something truly hard to believe given recent average load factors throughout the airline industry.  A check with the carrier concerned confirmed that 'only' might have been somewhat optimistic...but that the flight in question had departed on this segment with a load factor in the single digits; from a traveler's perspective, unimaginable comfort, although certainly a nightmare for an airline's chief financial officer.

The load factors experienced virtually industry-wide today would not have been believed (and would have been dismissed as 'impossible') at the start of the widebody era forty-plus years ago.  Back then only one industry sector -- charters --operated in the rarified atmosphere of routine load factors approaching three digits.  Scheduled service, individually-ticketed trips were considered to be doing very well if they exceeded sixty percent over any significant period of time.

Indeed, the advent of 747 service in 1970, and the widebodied tri-jets a year later often had the opposite effect on average seat occupancy, producing lower load factors in many markets where they were inserted, particularly if frequency was not reduced simultaneously.  Of course, since the U.S. industry was still subject to pervasive economic regulation, fares were set to achieve a break-even load factor in the 55 to 60 percent range.  A carrier that paid close attention to its costs could do even better; during the 1970s, National Airlines was profitable one year with a load factor just below 50 percent!

A service that put this in a different perspective was Eastern's "Air-Shuttle" in the Northeast.  The Shuttle operated on the basis of accommodating all passengers present at the gate as of departure time, rolling out additional, backup aircraft to operate 'extra sections'  (a term borrowed from the railroad industry; once during the 'roaring' 1920s, the New York Central Railroad operated a total of seven sections of its premier train, the Twentieth Century Limited,  in a single direction on one day) even if ...only one passenger was waiting once the scheduled equipment was filled.  (The late, and eminent, airline historian R. E. G. Davies points out that this first occurred within two months of the inaugural service on April 30, 1961, in his Airlines of the United States since 1914.)

While on the surface this would seem to be an appalling incidence of overcapacity, closer examination suggests a different result.  Mathematically, assuming that the additional aircraft had the same, or less, seating capacity than the regularly scheduled equipment, the overall load factor for that particular hour's departures (the Shuttle typically departed "on the hour", in both directions) never fell below 50 percent.  Indeed, if the extra section was filled to only 40 percent of its capacity, the overall load factor was 70 percent for that hour, a very respectable number considering the break even range cited above.

By the late 1970s, Eastern had achieved a de facto monopoly on the Shuttle routes.  As a result, and considering that theoretically there was unlimited capacity available (and indeed, multiple sections at peak times was commonplace by then), it was possible to gauge time-of-day demand in these markets via the publicly-available data submitted by the carrier to the CAB (Civil Aeronautics Board).  Interestingly, when examined on a directional basis, there were four different demand patterns, featuring varying degrees of peaking in the morning and afternoon/evening, although in the northbound Washington-New York market there was no morning peak; traffic built steadily throughout the morning.

As loads increased, and to cut down on the need for extra sections, Eastern acquired a pair of Airbus A300B2 aircraft configured specifically for Shuttle use in the Boston market; widebodies have never been permitted to operate routinely at Washington's Reagan National Airport.  The carrier later converted additional aircraft from its fleet of A300B4s to the Shuttle seating configuration to augment the original duo, which, in an interesting commentary on geopolitics, had served originally with Iran Air (and would later migrate to Alitalia, in Italy).

And of course, by this time, the Eastern Shuttle again had direct competition, a development that we'll look at further in the next installment.