Salvaging ships is the only way to get the necessary parts. If you have enough navigation data, you can buy Emergency Cartographic Data maps from the space station cartographer and use them instead of the Minotaur. Technically, any ship that the fabricator can assemble can be salvaged for parts, regardless of the source.

If you find a crashed ship that you can't salvage for wings/engines/cockpit, you can also salvage it for reasonably valuable scrap. If you're having trouble finding the right ship to salvage, you can use that money to buy the right ships to salvage. Fighters are more common in Vy’keen systems, haulers are more common in Gek systems, and explorers are more common in Korvax systems.