Synergetic Development Measure of Airport Groups Composite System and Its Influencing Factors Analysis: Some Evidence from China

Table 6

SDM model effect analysis of the factors influencing synergy.

Variables	Direct effects	Spillover effects
Air passenger throughput (h11)	0.2853	−0.1941
	(0.0345)	(0.0600)
Air cargo throughput (h12)	0.2003	0.1803
	(0.0218)	(0.0598)
Aircraft movements (h13)	0.1294	0.0517
	(0.0200)	(0.0421)
The number of air routes (h14)	0.0416	0.0147
	(0.0346)	(0.0518)
The number of airlines (h15)	0.1866	0.0193
	(0.0250)	(0.0425)
Urban GDP (h21)	—	—
Tertiary industry share (h22)	0.1554	0.1151
	(0.0413)	(0.0554)
Per capita disposable income (h23)	—	—
Resident population (h24)	0.1659	−0.0238
	(0.0216)	(0.0537)

Note. Values in parentheses are standard deviations; 10% significance; 5% significance; 1% significance.