A modest proposal on a more convenient transportation system between walled cities. 

Currently the best way of moving between cities is on airships. This is relatively safe, but not always the fastest, and can be quite expensive.

Teleportation magic is also expensive (unless you are skilled enough to do it yourself), and should only be done by the absolutely most adept magic users.

Walking, riding, and driving are all other options that can incur risk.

MY idea is to put a person into a mini pocket dimension, while equipped with an oxygen mask and tank.  This pocket dimension could then be loaded into some kind of magically powered trebuchet. It could be thrown great distances, and then guided down remotely by magic!

Upon landing the passengers could be safely removed, and risk would be negligible!

... unless the pocket dimension broke in some way, but I think that would be one of the least painful ways to go. Probably.

-Notes from public Researcher of Magica, Eddie "Sparkler" Flametongue