Portals are the favoured method of travel for most in the supernatural world. If you're a major magical power--like the Summer Court, the Parliament of Shadows, the Illuminati or the Veil Treaty--chances are you've got portals scattered across the globe.
The most notable network is that established by the Veil Treaty. It is centred on London, but travelling thorough its network allows one to reach any city with a Veil Council in the world--and there are over 3000 Veil Councils stretching from Iqaluit to Ushuaia and from Porto to Nuku'alofa. If you know the right paths, you can be in Anchorage one hour, and in Nairobi the next.
However, the Veil treaty's portal network is usually restricted for official purposes only, and are used mostly by diplomats, messengers, and the Veil Treaty's special agents--the Men in Black. They will occasionally consent to letting others make use of these portals, but it does require one to brave the Veil Treaty's sprawling bureaucracy to get the right permissions. And thus, it's usually better to just fly. Catching a red-eye from San Francisco to Tokyo may be quicker--and less painful--than getting permission to use the Veil's doors.
The other organizations are a bit more liberal with their portal networks--but only for members. Every supernatural being on the planet is technically part of the Veil Treaty, while you have to sign on to the Illuminati, the Templars, or the Assassins. And their networks are far less extensive. Sure, they can get you to places where the the Veil Treaty might not, but the Illuminati only have several hundred portals in their network--they can get you to major cities and financial centres, but if you're going to be heading to Siberia or the Rocky Mountains, it's probably best to ask to borrow a black helicopter.
Now, the Parliament of Shadows does one better than the Veil Treaty. They have doors that open into every closet, and beneath every bed, in the world. However, for one, they require a horror to open them. And for two, finding the right door can take hours of wandering Shadow--which usually isn't a pleasant experience for anyone who isn't a horror.