m3s have a much larger chance to reach the city and deliver the troops.
1) goon is detected 6k away, 3.5k if flying really low, but then a low dot is immediately suspected as a goon. m3 has very short icon range and is indistiguishable from a whirbl. Who wants to fly within 800 yards to see the ID tag?
2) goon has to drop the troops from 800+ feet. While they float down, they alert every GV and plane in the area. M3 can drive undetected all the way to the flag. While doing so, it is invisible to planes and defending GVs often have a broken line of sight to the M3 and its troops.
3) Goon has a long flight time from the nearest base that had not had its troops disabled. The distance to the M3 origin base is irrelevant - only the distace of the spawn to the town matters. The base can be 2 sectors away, or 10 miles away, but the GVs will spawn at a similar distance from the target town.
4) m3 typically has a shorter drive time to destination than goon flight time to destination. This means m3 will get killed and spawn repeatedly untill the defenders run out of ammo and have to land. When the defenders kill the c47 it is usually AFTER it wasted his long flying time.
5) good is totally defenseles when spotted. m3 can drive into indestructibles and wait to be resqued.
Is it any surprise that goons are not used when m3s are available?