I just discovered that DL has Y-UP fares to EGE out of many cities for this winter's ski season for $520 ai and up. Sample cities include FLL, GSP, CHS, AVL, TPA, BDL, etc.

SLC has lots of resorts that I love, and one very affordable option is to stay in the city and drive 30-45 minutes to a different resort each day. Access is easy. Pick each day's resort based on the morning's snow report.

For Colorado skiing, Delta has flights from ATL and/or other eastern hubs to DEN, EGE, HDN, ASE, and MTJ. DRO and GUC have sometimes been served with nonstops by DL. 25K awards from ATL to EGE are currently available for the upcoming ski season. Food and lodging can be expensive in the Vail area, but there are some deals to be found. Lift ticket prices can also be a shock. It's only about 25 miles from EGE to Beaver Creek. Just a few more to Vail.

Popular Canadian ski destinations include Whistler via YVR and Banff/Lake Louise via YYC.

Montana: BZN (for Big Sky)
Wyoming: JAC (Jackson Hole)

Connections through SLC offer even more options.

Be cautious of the type of aircraft into the smaller airports. It looks as if most days for ATL-MTJ will be on CRJ-900's. If weather is bad, the regional jets are more prone to cancellations or delays. EGE has lots of flights from DL and other airlines on 757s.

Beaver Creek and Vail offer free skiing on day of arrival into EGE. It's hard for most people to take advantage of that, IMO. I did it once and got in a couple hours at BC.

This delta.com page should help:
Ski Vacations and Flights to Top Ski Resorts on Delta.com