The best way to travel to Aspen depends on your preferences, budget, and time. There are four main airports that offer flights to Aspen: Aspen/Pitkin County Airport (ASE), Eagle County Airport (EGE), Grand Junction Regional Airport (GJT), and Denver International Airport (DIA). Each airport has its own advantages and disadvantages, such as:

Aspen/Pitkin County Airport (ASE):

This is the closest and most convenient airport to Aspen, as it is only three miles from the town center. You can take a free shuttle bus or a taxi to your hotel or ski resort. However, this airport is also the most expensive and has limited flight options. It may also be affected by bad weather or delays.

Eagle County Airport (EGE):

This airport is about 70 miles from Aspen, and offers more flight options than ASE. You can rent a car or take a shuttle service to Aspen, which takes about one and a half hours. The drive is scenic and easy, but you may encounter traffic or road closures during peak seasons.

Grand Junction Regional Airport (GJT):

This airport is about 130 miles from Aspen, and has fewer flight options than EGE. You can rent a car or take a shuttle service to Aspen, which takes about two and a half hours. The drive is longer and more winding, but you can enjoy the views of the Colorado River and the red rock formations.

Denver International Airport (DIA):

This airport is about 220 miles from Aspen, and has the most flight options and the lowest fares. You can rent a car or take a shuttle service to Aspen, which takes about four hours. The drive is the longest and most challenging, as you have to cross the Continental Divide and deal with traffic and weather conditions. However, you can also stop by some of the other ski resorts along the way, such as Breckenridge or Vail.
As you can see, there are many ways to get to Aspen by air, each with its own pros and cons. You can also choose to drive to Aspen from other nearby cities, such as Salt Lake City or Las Vegas, if you have more time and want to see more of the region.