At check-in at the airport, find out if you can return the stroller at the boarding gate. And if there is such a possibility, you can use the stroller until you board the plane. The airline employee will take it to the baggage compartment and return it to you after the flight, just like at the boarding ramp.
The stroller in the baggage compartment is transported according to the same rules as regular baggage and occupies a separate space. It is free of charge if you fly with a child. And if you're traveling without a baby, you'll need to pay for extra baggage space for the stroller. In doing so, take care to protect the stroller from damage. You can use a roomy plastic bag to pack, and removable fragile parts can be removed from the stroller and, if their size allows, carried in hand baggage.