Spock stated of Zeon ships, that the Zeons had "a crude interplanetary capability", and took no note of peculiarities in their known technology and the reaction powered Ekosian missile encountered by the USS Enterprise in 2268.
The Ekosians, believing the Enterprise was a Zeon spacecraft, launched their thermonuclear missile at the Enterprise, later stating that they repulsed "an attack by Zeon spacecraft," and that their "missiles utterly destroyed the enemy," much to the contrary.
Later, it was revealed that Melakon launched a space fleet sent to invade towards Zeon, using Zeon's own technology against them. The fleet carried with it "thousands of Ekosian spacemen." While Daras begged Kirk to have the Enterprise destroy the fleet, Kirk opted to revive John Gill and have him persuade the Ekosians to do it themselves. (TOS: "Patterns of Force")