Non-stop service becomes the norm as new aircraft, competition change the rules of airline service

Times have changed: Non-stops become a competitive necessity

Doubtless, much of the trend towards nonstop flights is rooted in aircraft technology and a willingness to redefine the nature of an "intercontinental" aircraft. Consequently, aircraft with greatly increased range and better economics, along with the use of smaller aircraft in the intercontinental sector, have reduced the need and demand for multi-stop flights. The use of B757s will make it possible for Continental to operate separate flights to Dublin and Shannon, replacing the one-stop or round-robin services that prevailed for many years.

The second factor that accounts for the demise of tag or multi-stop flights is the rise of alliances, bilateral and multilateral. Swissair, and later Swiss, flew to Singapore for decades-for a very brief period, nonstop. However most of that history included an en route stop at Bombay, Colombo or, more recently, Bangkok.

Last year, Swiss abandoned the BKK-SIN-BKK tag and now "operates" only as a codeshare partner on the Singapore nonstop flight from Zurich or with a Thai or Singapore connecting flight from Bangkok.

There are a number of drivers behind these changes:

• Passengers really prefer nonstop flights and if one exists, a competing service that involves a stop will be far less desirable;
• Flying large aircraft over short distances is expensive and, if there are traffic rights, provides interesting problems with space allocation. How many seats to sell on the tag without foregoing the more lucrative O & D passengers?
• Carriers with 5^th Freedom rights have problems with scheduling. To expand on the Swiss example, if there are passengers boarding in Bangkok and the aircraft arrives an hour early, the through passengers must wait for the scheduled departure time rather than proceeding onwards immediately;
• More carriers are deserting a dual-hub network. Varig operated a remarkably complex schedule as it tried to provide equal service from both Sao Paulo and Rio de Janeiro. TAM, its successor, has been clear that its primary hub is SAO and if RIO gets international service, they will be independent flights that serve a market need.

Substantial straightening over the past decade

The changes have been quite substantial for many carriers. The chart below shows the number of multiple-stop flight routings shown in the OAG for selected carriers in 2000, compared with 2010. Only long-haul flights were counted: no regional or domestic services are included.

2000		2010
Swissair	40	SWISS	6
Varig	36	GOL	0
Air France	40	Air France	12
JAL	27	JAL	0
TAP	23	TAP	6
SAA	18	SAA	5
KLM	43	KLM	30

Source: OAG

The differences are impressive in some cases - and the reasons vary by carrier.

• In the case of JAL, the carrier's entire schedule and network has been severely pruned since its Jan-2010 bankruptcy, and only direct long-haul flights have been maintained. An example of a discarded route (with no fifth freedom rights) was Tokyo-Vancouver-Sao Paulo);
• SAA, like Swiss, has terminated some own-metal services in favor of alliance partner flights;
• TAP has grown its presence and, with a fleet of A330s, is now able to operate directly between cities that previously were linked in series on a single flight;
• Some of the change with Air France and KLM has been the result of redefining areas of influence and eliminating some overlaps in the now-merged airline group.

Remaining multi-stops are mostly to ex-colonies

While multi-stage flights to the US, Europe or Asia have virtually disappeared, they remain the norm in other geographies, especially Africa and the Caribbean, where markets are thin. In 2000 Sabena operated 30 multi-sector flights - all to former African colonies. In 2010, the much smaller Brussels Airlines, with a network focused primarily on Europe and Africa, still operates 26.

Of the six Swiss multi-leg flights, 4 are to Africa. Both KLM and Air France have the bulk of their tag flights to Africa and the former colonial Caribbean islands. British Airways has a similar group of services from Gatwick to the islands with a British heritage.

In these cases either thin traffic flows or restrictive bilateral agreements, or a combination of both, dictate the service level.

Where there is limited demand, a more expensive (locally) tag operation is still less expensive than long haul O & D flights. Some of that problem may be solved by new aircraft about to begin service.

Domestic service patterns can influence joint terminal operations

There are also very significant differences between the domestic flight patterns of US carriers and the rest of the world, where short-haul flights are almost exclusively point-to-point.

Not so in the US where they abound, and every domestic multi-stop flight operated by a US legacy operates via a hub city and feeds/de-feeds a connecting bank. Thus the Toledo-Chicago-Minneapolis service works not because of the TOL/MSP demand but rather as a way to interconnect travelers actually bound from Toledo to Los Angeles and from Nashville to Minneapolis.

And, despite its claim not to have "hubs", most Southwest flights pass through a focus city during the rotation - again a phenomenon not found amongst its imitators in other geographies. The OAG list of Southwest's multi-sector flights spans over 11 pages. By contrast, Air Asia has none (although its long haul partner, AirAsia X now connects through onto the short haul operator).

Since most non-US carriers have a single hub, the absence of the pattern is understandable. However, despite the fact that Lufthansa has a dual hub network (FRA, MUC) it does not operate even one multi-stop domestic flight via a hub. The same is true of most other legacy carriers, worldwide, notable exceptions being Air India and Garuda Indonesia.

The unique US model - and when does a "direct" flight stop?

Thus the US model, consisting of numerous hubs or connecting points, has become unique to the American market. Furthermore, it is a common practice for US carriers to operate international services via a gateway city with a change of gauge. Between LaGuardia and Shanghai Delta operates flight 19 and United offers flight 835. But of course, both involve a change of aircraft and gauge: Delta over DTW with an A319 and United over ORD with an A320. This too, is an operating trick not evident in most other markets.

All of these various permutations have created terms to describe them. For instance, a "direct" flight can be either nonstop or with an intermediate stop. Therefore all non-stops are direct but not all direct flights are nonstop.

Nor does a through flight number necessarily mean a direct flight. A snowstorm at LaGuardia will not stop flight the New York-Shanghai DL19 service from landing in Shanghai - but you won't be on it.

As more efficient and longer-range aircraft enter airline fleets, the number of non-stops will continue to increase. The days of long haul multi-stop flights won't be over, but they will continue to decline.