the regulatory change from the viewpoints of load factor (i.e., the substitution of productivity), yield, and profit rate of each firm.

Figure 6-1 shows that there seems to be little difference of average load factor between 1979-1985 and 1986-1990, so we may say that the regulatory change hardly contributed to airlines' productivity. The average operating indices of all industries (including the airline industry) are down in that figure. It should be noted that the average load factor has something to do with the average operating rate of all the industries, which means that the load factor cyclically reflects both boom and recession. $ ^{11} $ In fact, the average load factor of the three airlines during 1986-1992 (67.1%), which includes the boom, is a little higher than during 1979-1985 (64.4%). However, from a statistical viewpoints, significant difference between them was not recognized as a result of a one-way layout analysis of variance $ (F=3.15 < F(1,40,0.05)=4.08) $ . So neither the regulatory change nor the boom could raise the load factor. On the other hand, from Figure 6-1, we can see that the crash of JAL's B747SR in 1985 had a substantial effect on its load factor that year.

Figures 7-1 and 7-2 show the yields of Japanese airlines (the international data are also included, because they are not separately published). Note that the real yields of JAL and JAS (shown in Figure 7-2) have been slightly decreasing, except for the boom whereas ANA's has been slightly increasing, and that even the nominal yield of those two firms (in Figure 7-1) have not necessarily increased. As JAL has been in operation mainly in international markets, so JAL may be suffering from the lack of revenue caused by discount fares in international markets. However, JAL has also been successful in being authorized to enter some domestic routes where discount tickets are less available than in international markets, which is expected to prevent the yield from decreasing. On the contrary, ANA is facing the opposite situation. ANA's yield may go down as the company goes on entering international markets. So ANA will aim at being authorized to enter domestic longer haul markets, where it can constantly keep more sufficient revenue.

With regard to JAS, after the regulatory change JAS came to operate in domestic major markets where coupon tickets are more available than in minor local routes in which the company used to operate. In addition, JAS was allowed to enter shorter-haul international markets, which may deprive it of its revenue. So JAS may suffer from the situation it faces after the regulatory change.

Finally, according to Figure 8, it seems that the profit rate became higher after the

$ ^{11} $ The correlation between domestic average load factor and average operation rate of all the industries is shown in the table below.

The correlation between average load factor and average operation rate of all industries

JAL	ANA	JAS	JAL( $ ^{85} $ was excluded)	ANA( $ ^{85} $ was excluded)	JAS( $ ^{85} $ was excluded)
all industries	0.556 (2.32 $ ^{*} $ )	0.565 (2.37 $ ^{*} $ )	0.611 (2.67 $ ^{*} $ )	0.669 (2.99 $ ^{**} $ )	0.626 (2.66 $ ^{*} $ )	0.662 (2.93 $ ^{**} $ )
service industries	0.744 (3.86 $ ^{***} $ )	0.280 (1.01)	0.110 (0.38)	0.704 (3.29 $ ^{***} $ )	0.296 (1.03)	0.132 (0.44)

Note : N=14('79-'92). Level of significance : * 5%, **2.5%, ***1%.