Delta often offers convenient single-connection itineraries via ATL with frequent same-day connections to Albany International Airport (ALB), making it a reliable choice for December travel from Birmingham-Shuttlesworth International Airport (BHM). American Airlines commonly routes through Charlotte Douglas International Airport (CLT), while United typically connects through hubs such as Chicago O'Hare (ORD) or Washington D.C. (IAD) depending on the schedule. For winter travel, Delta's ATL hub may present shorter connection windows but more flight options; American's CLT can be a good balance of frequency and price. Compare fare classes, included baggage allowances, and winter-weather rebooking policies—especially for December holiday travel. CTA: Use fare-comparison tools to filter by preferred carrier, baggage rules, and connection airport for December flights.