A few things of note regarding airline policies: Boots in a “boot bag” never count as a piece of checked luggage, so long as they accompany a pair of skis or a snowboard and the bag contains only boots.
Skis and snowboard bags are subject to the same set of rules across the board, meaning that they are not treated differently and are always a single piece of luggage assuming they follow the airline’s specific and individual regulations.
As you’ll see, airlines do differ in their size and weight restrictions, as well as in the cost of checking a bag. As with any other piece of luggage, the price to check your equipment depends on the airline and no airline has a specific ski or snowboard fee.
One pair of skis/snowboard and one boot bag containing only boots/bindings will be treated as a single item with the applicable checked bag charge ($25 for the first bag and $35 for the second, unless you have reached a certain status with the airline or have another means of waiving bag fees, such as an airline credit card).
Boot bags must not contain other items or exceed 45 linear inches (length + width + height) to be grouped as a single item with skis/snowboard. Boot bags that contain other articles will be subject to the excess baggage charge for a single piece.
Skis and snowboards up to 126 inches (320 cm) are allowed without an oversized fee.
Southwest Airlines allows up to two bags (containing one set of snow skis, ski poles and ski boots) to count as one item, even if they are packed and tagged separately (one ski bag and one boot bag). Skis, poles and snowboards must be encased in an appropriate container.
Since Southwest gives you two free bags, you can avoid all baggage fees even if you check your clothes.
A ski bag or one snowboard bag and one boot bag is accepted per person and counts as one checked bag.
The combined weight of the ski/snowboard bag and the boot bag may not exceed 50 lbs. or excess weight charges will apply, however no excess size charges are applicable. All standard baggage charges apply, meaning it is $25 for the first bag and $40 for the second, unless you have a means of waiving bag fees.
United accepts up to two snowboards in one bag or up to two pairs of skis and associated equipment in one bag to go along with a boot bag in either case. A boot bag on its own is subject to normal baggage fees.
Ski and boot bags must be less than 50 lbs. to avoid overweight charges. Service charges apply whenever bags are checked and are determined by the marketing carrier. Ski equipment in addition to the baggage allowance will be assessed at the excess baggage charge.
Skis (or snowboard), ski poles and ski boots all count as one checked bag. A pair of boots may be checked separate from the ski bag so long as it does not exceed 25 lbs. (if it does, it will be considered a separate bag). For example, one piece of luggage, one ski bag and a boot bag less than 25 lbs. equals two items, but a piece of luggage, one ski bag and one boot bag over 25 lbs. would equal three.
Checked, carry-on and overweight fees (for a bag over 50 lbs.) apply; oversize charges do not apply.
One or more sets of skis and poles carried together in the same container count as one piece of checked baggage (ski poles that are carried separately will count as a piece of checked baggage, so make sure you pack them in with the skis). Skis and poles must be packed in a rigid and/or hard shell case specifically designed for shipping. The policies for a snowboard are the same. There are no oversize charges for skis or snowboards, but overweight charges will apply (must be less than 50 lbs.).
A boot bag containing only boots does not count as a piece of checked baggage if it's carried along with skis/snowboard; but if said bag is unaccompanied or found to be transporting items in addition to boots, it's a separate check for you.