Dave ,
It depends on the scale as to how I mount them. For 1/72 and 1/48 scale I simply drill into the tires and insert a brass pin then into the drilled holes on the base. For 1/32 and larger (WW II) I usually will drill through the base and then counter sink it then use a small screws to hold the plane to the base. WW I models I do just as with the smaller scales with the exception of using larger brass pins.
Highest Regards,
Gregory Jouette