Delta's policies regarding checking strollers, car seats, mobility devices and sports equipment.
Sports Items - Several sports items like skis and fishing equipment count toward the checked-in luggage allowance (thus for some destinations it may cost you what it would cost to check in your first or second piece of luggage, whereas for other international ones it may qualify to be checked in for free).
Heavier/larger equipment, such as bicycles and scuba dive tanks, for the most part, may be checked for a cost of $175 - $300 per direction.
The following sports items are not permitted at check-in (you can contact their cargo department to send it as freight - more expensive) - kayaks, canoes, javelins.
Strollers, Car Seats - Transported free of charge.
Mobility Devices - Wheelchairs, scooters, braces, etc. are accepted free of charge as checked baggage and do not count as part of the checked luggage allowance.