Problem with sending anything through the metaplanes is that you can't really take physical forms with you and if you exit in a mana void you're pretty likely to just explode.

What you might be able to do is take the possessed world tree idea and expand it to more of a grove. Have the tree-hugger space-faring mages be an inhabitation tradition and inhabit each tree in the grove with a plant spirit that can use the Movement power. House rule something allowing the Body restriction of Movement to be circumvented by having a group of spirits all using the power at once on the same heavy object, something like the combined force of each spirit being used to determine the max body of the target able to be affected by the power. Considering that the max speed record of a space shuttle on re-entry was 8000 m/s and that 270+ years in the future at shadowrun technological development levels will put us at something significantly higher than that, then multiplying by around 6 for magic and you'll have a ship pushing the speed of light, or even exceeding it if you're being generous and saying fuck you to physics in favor of magic. You still won't be able to travel the stars in anything like a hurry but you'll be able to at least have a chance of making it to Alpha Centauri before having all your passengers die of old age.

As for the human feces as fertilizer idea, I suggested it as a way of creating a circulating, natural system on board the ship reminiscent of Earth, which should create a more powerful manasphere. And if the people providing the fertilizer are all being fed by the regenerating magic trees at the center of the ship then it won't be corrupted industrialized poo, it'll be magic poo. So the secret to interstellar travel is magic poo

What if the spirit inhabits the ship directly? Would't its body be the body rating of the ship? Which is usually really really high? I could foresee such a thing having body of well over 40. An alt thought, for OMG amounts of Karma one could construct an ally spirit with a space ship form. It would explain cabbits in Tenchi.

Having a spirit Inhabit a ship wouldn't do anything to help its speed, the ship would still have a body well over double the spirit's force and would still be immune to its own Movement power. As for Ally spirits with a spaceship form, only if your tradition had something to do with worshipping rockets (yay Fallout 3?), and even then they wouldn't have their own biosphere or aspected background count to counteract the space void around them.

Actually, there are precedences for venerating space travel. Ok, How hard and fast is the law about not moving wards?

As per the FAQ, not very. So long as you keep the center of the ward from moving in relation to the shape that it's warding the ward won't deform and even a few centimeters in any direction won't be a problem. A shock-braced pillar in the center of a ship would be a perfect anchor for a ward that was placed on the ship's hull.

So could you "Seal in" the magic on the ship with a large enough ward?

I don't think so. Even if you ruled that the ward itself wouldn't be affected by the void around it (and it would have to be a damn powerful ward to accomplish that considering that a mage can only produce a ward with a force equal to twice his magic attribute and space has a -12 mana void, meaning that a magic 7 mage would have to resist 13P drain to create it and spend 13 karma to make it permanent in order to make a ward that would function as force 1 in space) there's nothing saying that a ward would capture and contain the mana inside it if moved. You could, of course, houserule this, but it seems like based on the nature of mana, this contained mana would be drained by the use of magic like oxygen tanks and wouldn't last long before becoming a mana void in and of itself. Living things would slowly contribute to this void but Awakened would unconsciously drain from it, meaning that in order to make it sustainable you would either have to have a lot of non-Awakened living things on the ship or very few Awakened.

Could you lengthen the time required to make the ward an make the drain less, and can a group of magi construct a ward together, assuming of course that they follow the same basic tradition?

By RAW, no and yes, although each mage who makes the ward would take the same drain. There are no rules for extending the time required to form a ward to lessen the drain and I would hesitate to create them as that could mean that decent Magic players could form a force 10 or 12 ward around their house by spending a day doing it with very little penalty. The rules for having groups of mages create a ward exist to extend the area of a ward and each mage still has to resist drain equal to the force of the ward.

Edit: the rules for wards are listed on page 194 SR4a (185 BBB) and are extended on page 123 SM

cool. I think I am going to use some handwavium and say thats how it happens