Airport Trailers settings. 
If you have Modloader then the Vehicles.ide, Handling.cfg, Carcols.dat and Carmods.dat settings can 
be simply installed by copying this file in a folder inside ModLoader directory.
Example: 
GTA San Andreas\modloader\airport trailers\Settings.txt

Replace the default line in Vehicles.ide with this one:
606, 	bagboxa, 	bagboxa, 	trailer,	BAGBOXA, 	BAGBOXA, 	null,	ignore,	 	4,	0,	0,		-1, 0.42, 0.42,		-1
607, 	bagboxb, 	bagboxb, 	trailer,	BAGBOXB, 	BAGBOXB, 	null,	ignore,	 	4,	0,	0,		-1, 0.42, 0.42,		-1

Replace the default line in Handling.cfg with this one:
BAGBOXA      1000.0    1354.2   5.0    0.0 0.4 -0.2  70  1.00 0.85 0.5  	3 160.0 20.0 30.0 R E 	5.0   0.50 0 30.0  	2.0  0.09  0.0   0.05 -0.07 0.5  0.0		0.26 0.50  10000 	3100		4			1  1	0
BAGBOXB      1000.0    1354.2   5.0    0.0 0.4 -0.2  70  1.00 0.85 0.5  	3 160.0 20.0 30.0 R E 	5.0   0.50 0 30.0  	2.0  0.09  0.0   0.05 -0.07 0.5  0.0		0.26 0.50  10000 	3100		4			1  1	0