Aspen Airport, ASE, serves two major resort areas the town of Aspen and its three ski mountains Ajax, Buttermilk where the ESPN Winter X Games are held every year and Aspen Highlands. Other parts surrounding Aspen severed by Aspen airport shuttle services are Woody Creek, Red Mountain and Mountain Estates out past the Aspen Club on Hy 82, heading up Independence Pass.
Snowmass which is in the opposite direction from Aspen is the largest single ski resort in the USA, with thousands of acres of skiing and two base mountains. The old Snowmass base village and the new tree house base village, which is located around a mile away downhill form the Snowmass Base Village, are still under construction. Snowmass has lots of homes on Wood Road, Faraway Road and Continental Divide Road, which is the back way to Old Snowmass which is a separate area itself and around Snowmass there are also some large subdivisions like Two Creeks and Fox Run.
For most people flying in to Aspen Colorado from other parts of the USA; airport shuttles are pretty common at most any major US airport like LAX, SFO, and DIA. Aspen has one company that is licensed as an airport shuttle and lots of luxury limousines and one taxi service that can multi-load out of the airport, but they are fractional meter rather than a set rate by zone like a true airport shuttle, and as such do not offer the same inexpensive fares that people expect when they take an airport shuttle. The market is further confused as there is an airport shuttle service that goes to Eagle Vail airport and a bus company that also runs shuttle service between Aspen and Denver International airport the difference being that they serve the airports as their core business.
The idea of an airport shuttle is that they pick up and drop off at different locations including homes, hotels, condos, business and even bus and train stations and for some larger cities they also will go airport to airport for instance LAX to John Wayne or LAX to Burbank or Burbank to John Wayne. As such, Aspen and Snowmass are ideal for airport shuttles as the main road, Colorado Highway 82 runs east and west and there are really few roads that run in right angles for any real distance, going east those would be Maroon Creek, Castle Creek and Cemetery lane, everything else is on a straight line more or less with just a few areas off the line, but those would be the natural last drop offs anyway as they are the furthest away. And going west to Snowmass there are only two choices of road, Owl Creek and the more popular Brush Creek.